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Main
Date: 08 Nov 2007 21:47:45
From: jim beam
Subject: dual pivot brake caliper toe progression
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for the skeptics.
http://www.flickr.com/photos/38636024@N00/1928128941/
http://www.flickr.com/photos/38636024@N00/1928128939/
http://www.flickr.com/photos/38636024@N00/1928128923/
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Date: 13 Nov 2007 19:37:40
From: damyth
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 11, 9:01 am, unforgive...@juno.com wrote:
> On Nov 10, 9:19 am, jim beam <spamvor...@bad.example.net> wrote:
>
>
>
> > unforgive...@juno.com wrote:
> > > On Nov 9, 10:49 pm, jim beam <spamvor...@bad.example.net> wrote:
> > >> unforgive...@juno.com wrote:
> > >>> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
> > >>>> unforgive...@juno.com wrote:
> > >>>>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> > >>>>>> for the skeptics.
> > >>>>>>http://www.flickr.com/photos/38636024@N00/1928128941/
> > >>>>>>http://www.flickr.com/photos/38636024@N00/1928128939/
> > >>>>>>http://www.flickr.com/photos/38636024@N00/1928128923/
> > >>>>> What about a picture from the side? If the pads aren't parallel to
> > >>>>> the mounting bolt, this proves absolutely nothing.
> > >>>> It's difficult to tell from the photos, but it appears that there is an
> > >>>> eccentric motion to the pad on the right. As the brake closes, the
> > >>>> right pad not only moves towards the other pad but also forward (down,
> > >>>> in the photo). This could be explained by the pivots not being parallel
> > >>>> to each other.
> > >>> That's the great thing about orbital pad adjustment. You can make it
> > >>> look like all kinds of neat things are happening if you only took at
> > >>> the brake from one direction. Square the pads up like they would be
> > >>> on a bike (where some of us use our brakes) and the eccentricity goes
> > >>> away.
> > >> bullshit. that caliper [d-a 7700, non-orbital pads] is straight off a
> > >> bike. the pads are exactly as they were when operating on the rim and
> > >> haven't been touched.
>
> > > Straight off a bike? In the other thread, you said it was new in box.
>
> > >>> It's interesting that jim isn't even trying to show a front
> > >>> brake doing the opposite.
> > >> what the fuck is up with you idiots? first it doesn't happen. then
> > >> it's "optical tricks". now, you want me to strip my bike down again
> > >> because the evidence that supports what i've been saying all along
> > >> somehow needs to be re-presented? strip your own fucking bike, examine
> > >> your own fucking caliper and take your own fucking pics.
>
> > > Pictures like these?
> > >http://s223.photobucket.com/albums/dd171/unforgiven99/?action=view&cu...
> > > That's an RX100 front dual pivot, 1990 or so vintage, but the bushings
> > > are all snug.
>
> > > The top row shows progressivetoein, but with the pads pointing up
> > > from horizontal. In other words exactly how the wouldn't be on the
> > > bike.
> > > Row two, the caliper was set up with the pads pointing just a little
> > > bit farther down from horizontal than they would be in operation, and
> > > the result is a noticeableprogressiontotoeout.
> > > The pads are non-orbital, and there is no appearance of fore-aft
> > > translation in either position.
>
> > > Now, you can call names all you want, but it doesn't make anything
> > > that you've said or shown us evidence of front/rear non-
> > > interchangeability. I'll let you back up, split some hairs, and claim
> > > that Shimano changed their design for dual pivots between my old RX100
> > > and your new Dura-Ace. I'll even accept it if you can figure out a
> > > way to prove that the second pivot on your brake is off axis with the
> > > mounting bolt, but I will not take pictures of brake pads as
> > > evidence. They don't prove anything.
>
> > but your caliper still showstoeprogression!!! compare with single
> > pivot!!!
>
> > [kinda speechless.]
>
> Speechless? You're so much more fun when you have something to say.
> Are you speechless because you can't remember where you got your brake
> caliper from, speechless because you can't remember if you think
> single pivot mechanisms are irrelevant, or speechless because my
> pictures show toeing in and out with the same caliper? That's because
> the pads are showingtoeprogression, not the caliper. And in the
> orientation they would be on the front end of a bike, the pads
> progress totoeout. Which is exactly the opposite of what you claim
> they were designed to do. This is why we aren't to be looking at the
> pads.
> I can tell you why the sky is blue, and I can show you some pictures
> of the sky being blue, but you seem to insist on covering your ears,
> staring at the ground and yelling that the sky is green. As much fun
> as it is to make a supposed retiree lash out like a petulant pre-teen
> and continue to kick him while he's down, this is really starting to
> bore me.
Nominate for POTM. That's Punk'd of the Month. I've never seen
anyone stop Mr. Southern Comfort dead. :)
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Date: 11 Nov 2007 09:12:25
From:
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 11, 1:56 am, carlfo...@comcast.net wrote:
> On Nov 10, 8:16 pm, jobst.bra...@stanfordalumni.org wrote:
>
> [snip]
>
> > What more do you want. A coil about the center-bolt causes neither
> > end of the spring to foreshorten, articulating about the same pivot
> > caliper arms do. Basta!
>
> > Jobst Brandt
>
> Dear Jobst,
>
> With our dangerously fragile wheels and perilously over-priced
> bicycles, are any brakes a good idea?
>
> "There are many arguments for and against it, but one thing is certain
> and that is that the brake is not a popular attachment. Few riders of
> experience use it, and a novice is inclined to look upon it as an
> unnecessary article. An expert has said that many of this year's
> wheels are so constructed as to make the addition of brakes very
> undesirable. He points out that many wheels are not strong enough to
> withstand the use of brakes, and refers to the cost as an obstacle to
> many. The minimum expense would seldom be less than $1.50, while the
> average would be nearer $3."
>
> --NYT Feb. 2, 1896, "Gossip of the Cyclers"
>
> http://query.nytimes.com/gst/abstract.html?res=9A0CE4DD143BEE33A25751...
>
> Cheers,
>
> Carl Fogel
I think CarbonSports is the only company to step right up and tell
customers to lay off the brakes.
"The "L'Alpe d'Huez" wheelset has been developed specifically for the
demands of uphill time trials. To achieve the least possible rotary
mass, the rim's brake surfaces have been lightened. Thus, the brakes
must be used sparingly and not with brute force. Only use these wheels
in flat or uphill sections. They are not designed for the braking
forces encountered when riding downhill."
At $5500 a pair retail, a panic stop could get expensive.
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Date: 11 Nov 2007 09:01:54
From:
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 10, 9:19 am, jim beam <spamvor...@bad.example.net > wrote:
> unforgive...@juno.com wrote:
> > On Nov 9, 10:49 pm, jim beam <spamvor...@bad.example.net> wrote:
> >> unforgive...@juno.com wrote:
> >>> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
> >>>> unforgive...@juno.com wrote:
> >>>>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> >>>>>> for the skeptics.
> >>>>>>http://www.flickr.com/photos/38636024@N00/1928128941/
> >>>>>>http://www.flickr.com/photos/38636024@N00/1928128939/
> >>>>>>http://www.flickr.com/photos/38636024@N00/1928128923/
> >>>>> What about a picture from the side? If the pads aren't parallel to
> >>>>> the mounting bolt, this proves absolutely nothing.
> >>>> It's difficult to tell from the photos, but it appears that there is an
> >>>> eccentric motion to the pad on the right. As the brake closes, the
> >>>> right pad not only moves towards the other pad but also forward (down,
> >>>> in the photo). This could be explained by the pivots not being parallel
> >>>> to each other.
> >>> That's the great thing about orbital pad adjustment. You can make it
> >>> look like all kinds of neat things are happening if you only took at
> >>> the brake from one direction. Square the pads up like they would be
> >>> on a bike (where some of us use our brakes) and the eccentricity goes
> >>> away.
> >> bullshit. that caliper [d-a 7700, non-orbital pads] is straight off a
> >> bike. the pads are exactly as they were when operating on the rim and
> >> haven't been touched.
>
> > Straight off a bike? In the other thread, you said it was new in box.
>
> >>> It's interesting that jim isn't even trying to show a front
> >>> brake doing the opposite.
> >> what the fuck is up with you idiots? first it doesn't happen. then
> >> it's "optical tricks". now, you want me to strip my bike down again
> >> because the evidence that supports what i've been saying all along
> >> somehow needs to be re-presented? strip your own fucking bike, examine
> >> your own fucking caliper and take your own fucking pics.
>
> > Pictures like these?
> >http://s223.photobucket.com/albums/dd171/unforgiven99/?action=view&cu...
> > That's an RX100 front dual pivot, 1990 or so vintage, but the bushings
> > are all snug.
>
> > The top row shows progressive toe in, but with the pads pointing up
> > from horizontal. In other words exactly how the wouldn't be on the
> > bike.
> > Row two, the caliper was set up with the pads pointing just a little
> > bit farther down from horizontal than they would be in operation, and
> > the result is a noticeable progression to toe out.
> > The pads are non-orbital, and there is no appearance of fore-aft
> > translation in either position.
>
> > Now, you can call names all you want, but it doesn't make anything
> > that you've said or shown us evidence of front/rear non-
> > interchangeability. I'll let you back up, split some hairs, and claim
> > that Shimano changed their design for dual pivots between my old RX100
> > and your new Dura-Ace. I'll even accept it if you can figure out a
> > way to prove that the second pivot on your brake is off axis with the
> > mounting bolt, but I will not take pictures of brake pads as
> > evidence. They don't prove anything.
>
> but your caliper still shows toe progression!!! compare with single
> pivot!!!
>
> [kinda speechless.]
Speechless? You're so much more fun when you have something to say.
Are you speechless because you can't remember where you got your brake
caliper from, speechless because you can't remember if you think
single pivot mechanisms are irrelevant, or speechless because my
pictures show toeing in and out with the same caliper? That's because
the pads are showing toe progression, not the caliper. And in the
orientation they would be on the front end of a bike, the pads
progress to toe out. Which is exactly the opposite of what you claim
they were designed to do. This is why we aren't to be looking at the
pads.
I can tell you why the sky is blue, and I can show you some pictures
of the sky being blue, but you seem to insist on covering your ears,
staring at the ground and yelling that the sky is green. As much fun
as it is to make a supposed retiree lash out like a petulant pre-teen
and continue to kick him while he's down, this is really starting to
bore me.
|
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Date: 10 Nov 2007 22:56:26
From:
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 10, 8:16 pm, jobst.bra...@stanfordalumni.org wrote:
[snip]
> What more do you want. A coil about the center-bolt causes neither
> end of the spring to foreshorten, articulating about the same pivot
> caliper arms do. Basta!
>
> Jobst Brandt
Dear Jobst,
With our dangerously fragile wheels and perilously over-priced
bicycles, are any brakes a good idea?
"There are many arguments for and against it, but one thing is certain
and that is that the brake is not a popular attachment. Few riders of
experience use it, and a novice is inclined to look upon it as an
unnecessary article. An expert has said that many of this year's
wheels are so constructed as to make the addition of brakes very
undesirable. He points out that many wheels are not strong enough to
withstand the use of brakes, and refers to the cost as an obstacle to
many. The minimum expense would seldom be less than $1.50, while the
average would be nearer $3."
--NYT Feb. 2, 1896, "Gossip of the Cyclers"
http://query.nytimes.com/gst/abstract.html?res=9A0CE4DD143BEE33A25751C0A9649C94679ED7CF
Cheers,
Carl Fogel
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Date: 10 Nov 2007 13:19:18
From: Joe Riel
Subject: Re: dual pivot brake caliper toe progression
|
luns@mochi.EECS.Berkeley.EDU (Luns Tee) writes:
> In article <4tOdnQOIK5p9IKjanZ2dnUVZ_urinZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>>> Now, you can call names all you want, but it doesn't make anything
>>> that you've said or shown us evidence of front/rear non-
>>> interchangeability. I'll let you back up, split some hairs, and claim
>>> that Shimano changed their design for dual pivots between my old RX100
>>> and your new Dura-Ace. I'll even accept it if you can figure out a
>>> way to prove that the second pivot on your brake is off axis with the
>>> mounting bolt, but I will not take pictures of brake pads as
>>> evidence. They don't prove anything.
>>>
>>
>>but your caliper still shows toe progression!!!
>
> These photos show quite clearly that the same front caliper can
> have toe-in or toe-out as the caliper closes with just the change of the
> pad angle. This is not a function of front calipers being different from
> rear calipers as you've claimed, it's a matter of the pads being
> mounted at different angles in either application.
>
>>compare with single pivot!!!
>
> No difference.
>
> http://www.OCF.Berkeley.EDU/~tee/rbt/toe/DSC01855.JPG
> http://www.OCF.Berkeley.EDU/~tee/rbt/toe/DSC01851.JPG
These would be slightly easier to compare if you hadn't rotated one of
them 180 degrees.
--
Joe Riel
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Date: 10 Nov 2007 05:54:32
From:
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 10:49 pm, jim beam <spamvor...@bad.example.net > wrote:
> unforgive...@juno.com wrote:
> > On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
> >> unforgive...@juno.com wrote:
> >>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> >>>> for the skeptics.
> >>>>http://www.flickr.com/photos/38636024@N00/1928128941/
> >>>>http://www.flickr.com/photos/38636024@N00/1928128939/
> >>>>http://www.flickr.com/photos/38636024@N00/1928128923/
> >>> What about a picture from the side? If the pads aren't parallel to
> >>> the mounting bolt, this proves absolutely nothing.
> >> It's difficult to tell from the photos, but it appears that there is an
> >> eccentric motion to the pad on the right. As the brake closes, the
> >> right pad not only moves towards the other pad but also forward (down,
> >> in the photo). This could be explained by the pivots not being parallel
> >> to each other.
>
> > That's the great thing about orbital pad adjustment. You can make it
> > look like all kinds of neat things are happening if you only took at
> > the brake from one direction. Square the pads up like they would be
> > on a bike (where some of us use our brakes) and the eccentricity goes
> > away.
>
> bullshit. that caliper [d-a 7700, non-orbital pads] is straight off a
> bike. the pads are exactly as they were when operating on the rim and
> haven't been touched.
>
Straight off a bike? In the other thread, you said it was new in box.
> > It's interesting that jim isn't even trying to show a front
> > brake doing the opposite.
>
> what the fuck is up with you idiots? first it doesn't happen. then
> it's "optical tricks". now, you want me to strip my bike down again
> because the evidence that supports what i've been saying all along
> somehow needs to be re-presented? strip your own fucking bike, examine
> your own fucking caliper and take your own fucking pics.
Pictures like these?
http://s223.photobucket.com/albums/dd171/unforgiven99/?action=view¤t=Presentation1.jpg
That's an RX100 front dual pivot, 1990 or so vintage, but the bushings
are all snug.
The top row shows progressive toe in, but with the pads pointing up
from horizontal. In other words exactly how the wouldn't be on the
bike.
Row two, the caliper was set up with the pads pointing just a little
bit farther down from horizontal than they would be in operation, and
the result is a noticeable progression to toe out.
The pads are non-orbital, and there is no appearance of fore-aft
translation in either position.
Now, you can call names all you want, but it doesn't make anything
that you've said or shown us evidence of front/rear non-
interchangeability. I'll let you back up, split some hairs, and claim
that Shimano changed their design for dual pivots between my old RX100
and your new Dura-Ace. I'll even accept it if you can figure out a
way to prove that the second pivot on your brake is off axis with the
mounting bolt, but I will not take pictures of brake pads as
evidence. They don't prove anything.
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| | |
Date: 10 Nov 2007 16:12:15
From:
Subject: Re: dual pivot brake caliper toe progression
|
Someone writes:
http://www.flickr.com/photos/38636024@N00/1928128941/
http://www.flickr.com/photos/38636024@N00/1928128939/
http://www.flickr.com/photos/38636024@N00/1928128923/
>>>>> What about a picture from the side? If the pads aren't parallel
>>>>> to the mounting bolt, this proves absolutely nothing.
>>>> It's difficult to tell from the photos, but it appears that there
>>>> is an eccentric motion to the pad on the right. As the brake
>>>> closes, the right pad not only moves toward the other pad but
>>>> also forward (down, in the photo). This could be explained by
>>>> the pivots not being parallel to each other.
>>> That's the great thing about orbital pad adjustment. You can make
>>> it look like all kinds of neat things are happening if you only
>>> took at the brake from one direction. Square the pads up like
>>> they would be on a bike (where some of us use our brakes) and the
>>> eccentricity goes away.
>> bullshit. that caliper [d-a 7700, non-orbital pads] is straight
>> off a bike. the pads are exactly as they were when operating on
>> the rim and haven't been touched.
> Straight off a bike? In the other thread, you said it was new in
> box.
>>> It's interesting that jim isn't even trying to show a front brake
>>> doing the opposite.
>> what the fuck is up with you idiots? first it doesn't happen.
>> then it's "optical tricks". now, you want me to strip my bike down
>> again because the evidence that supports what i've been saying all
>> along somehow needs to be re-presented? strip your own fucking
>> bike, examine your own fucking caliper and take your own fucking
>> pics.
> Pictures like these?
http://tinyurl.com/2lbul4
> That's an RX100 front dual pivot, 1990 or so vintage, but the
> bushings are all snug.
> The top row shows progressive toe in, but with the pads pointing up
> from horizontal. In other words exactly how the wouldn't be on the
> bike.
> Row two, the caliper was set up with the pads pointing just a little
> bit farther down from horizontal than they would be in operation,
> and the result is a noticeable progression to toe out. The pads are
> non-orbital, and there is no appearance of fore-aft translation in
> either position.
> Now, you can call names all you want, but it doesn't make anything
> that you've said or shown us evidence of front/rear non-
> interchangeability. I'll let you back up, split some hairs, and
> claim that Shimano changed their design for dual pivots between my
> old RX100 and your new Dura-Ace. I'll even accept it if you can
> figure out a way to prove that the second pivot on your brake is off
> axis with the mounting bolt, but I will not take pictures of brake
> pads as evidence. They don't prove anything.
As I mentioned, the two legs of the dual pivot brake pivot around
different centers, the center bolt and one offset to one side, both
intended to engage a rim centered in the fork. That causes cosine
error and that causes the short arm to change the attitude of its end
with respect to the longer arm as it sweeps through its path.
The dual pivot caliper is a dud. Brake centering can be accomplished
with a properly designed return spring, one that is coiled about the
center post rather than the common coils offset to either side. Such
a brake was shown at InterBike by an unknown Vietnamese producer. I
designed one of these return springs for my old Campagnolo record
brake years ago. The dual pivot is an example of a bicycle design
that missed the point.
Jobst Brandt
|
| | |
Date: 10 Nov 2007 15:53:03
From:
Subject: Re: dual pivot brake caliper toe progression
|
Someone writes:
http://www.flickr.com/photos/38636024@N00/1928128941/
http://www.flickr.com/photos/38636024@N00/1928128939/
http://www.flickr.com/photos/38636024@N00/1928128923/
>>>>> What about a picture from the side? If the pads aren't parallel
>>>>> to the mounting bolt, this proves absolutely nothing.
>>>> It's difficult to tell from the photos, but it appears that there
>>>> is an eccentric motion to the pad on the right. As the brake
>>>> closes, the right pad not only moves toward the other pad but
>>>> also forward (down, in the photo). This could be explained by
>>>> the pivots not being parallel to each other.
>>> That's the great thing about orbital pad adjustment. You can make
>>> it look like all kinds of neat things are happening if you only
>>> took at the brake from one direction. Square the pads up like
>>> they would be on a bike (where some of us use our brakes) and the
>>> eccentricity goes away.
>> bullshit. that caliper [d-a 7700, non-orbital pads] is straight
>> off a bike. the pads are exactly as they were when operating on
>> the rim and haven't been touched.
> Straight off a bike? In the other thread, you said it was new in
> box.
>>> It's interesting that jim isn't even trying to show a front brake
>>> doing the opposite.
>> what the fuck is up with you idiots? first it doesn't happen.
>> then it's "optical tricks". now, you want me to strip my bike down
>> again because the evidence that supports what i've been saying all
>> along somehow needs to be re-presented? strip your own fucking
>> bike, examine your own fucking caliper and take your own fucking
>> pics.
> Pictures like these?
http://tinyurl.com/2lbul4
> That's an RX100 front dual pivot, 1990 or so vintage, but the
> bushings are all snug.
> The top row shows progressive toe in, but with the pads pointing up
> from horizontal. In other words exactly how the wouldn't be on the
> bike.
> Row two, the caliper was set up with the pads pointing just a little
> bit farther down from horizontal than they would be in operation,
> and the result is a noticeable progression to toe out. The pads are
> non-orbital, and there is no appearance of fore-aft translation in
> either position.
> Now, you can call names all you want, but it doesn't make anything
> that you've said or shown us evidence of front/rear non-
> interchangeability. I'll let you back up, split some hairs, and
> claim that Shimano changed their design for dual pivots between my
> old RX100 and your new Dura-Ace. I'll even accept it if you can
> figure out a way to prove that the second pivot on your brake is off
> axis with the mounting bolt, but I will not take pictures of brake
> pads as evidence. They don't prove anything.
As I mentioned, the two legs of the dual pivot brake pivot around
different centers, the center bolt and one offset to one side, both
intended to engage a rim centered in the fork. That causes cosine
error and that causes the short arm to change the attitude of its end
with respect to the longer arm as it sweeps through its path.
The dual pivot caliper is a dud. Brake centering can be accomplished
with a properly designed return spring, one that is coiled about the
center post rather than the common coils offset to either side. Such
a brake was shown at InterBike by an unknown Vietnamese producer. I
designed have such a return spring for my old Campagnolo record brake.
The dual pivot is an example of a bicycle design that missed the
point.
Jobst Brandt
|
| | | |
Date: 10 Nov 2007 23:40:34
From: Helmut Springer
Subject: Re: dual pivot brake caliper toe progression
|
jobst.brandt@stanfordalumni.org wrote:
> The dual pivot caliper is a dud. Brake centering can be
> accomplished with a properly designed return spring, one that is
> coiled about the center post rather than the common coils offset
> to either side.
SunTour built that long ago, my GPX stay centered...
> Such a brake was shown at InterBike by an unknown Vietnamese
> producer.
Would be nice to have that again on the market, in at least decent
quality.
--
MfG/Best regards
helmut springer panta rhei
|
| | | | |
Date: 11 Nov 2007 03:16:26
From:
Subject: Re: dual pivot brake caliper toe progression
|
Helmut Springer writes:
>> The dual pivot caliper is a dud. Brake centering can be
>> accomplished with a properly designed return spring, one that is
>> coiled about the center post rather than the common coils offset to
>> either side.
> SunTour built that long ago, my GPX stay centered...
>> Such a brake was shown at InterBike by an unknown Vietnamese
>> producer.
> Would be nice to have that again on the market, in at least decent
> quality.
I would have included a link if I had one. I think the problem of the
return spring is so blatantly obvious on any dual pivot caliper that
it is better to see it in person. The return spring articulates about
a theoretical point in the center of the return spring coil, the
foreshortening is visible as the caliper is exercised in that the
spring moves substantially in the plastic sleeve. Single pivot brakes
have two of these sliding places encrusted in the road dirt where
their ends bear on the caliper. These points do not change in sliding
friction identically, so one arm retracts, the other doesn't.
What more do you want. A coil about the center-bolt causes neither
end of the spring to foreshorten, articulating about the same pivot
caliper arms do. Basta!
Jobst Brandt
|
| | |
Date: 10 Nov 2007 06:19:12
From: jim beam
Subject: Re: dual pivot brake caliper toe progression
|
unforgiven99@juno.com wrote:
> On Nov 9, 10:49 pm, jim beam <spamvor...@bad.example.net> wrote:
>> unforgive...@juno.com wrote:
>>> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>>>> unforgive...@juno.com wrote:
>>>>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> for the skeptics.
>>>>>> http://www.flickr.com/photos/38636024@N00/1928128941/
>>>>>> http://www.flickr.com/photos/38636024@N00/1928128939/
>>>>>> http://www.flickr.com/photos/38636024@N00/1928128923/
>>>>> What about a picture from the side? If the pads aren't parallel to
>>>>> the mounting bolt, this proves absolutely nothing.
>>>> It's difficult to tell from the photos, but it appears that there is an
>>>> eccentric motion to the pad on the right. As the brake closes, the
>>>> right pad not only moves towards the other pad but also forward (down,
>>>> in the photo). This could be explained by the pivots not being parallel
>>>> to each other.
>>> That's the great thing about orbital pad adjustment. You can make it
>>> look like all kinds of neat things are happening if you only took at
>>> the brake from one direction. Square the pads up like they would be
>>> on a bike (where some of us use our brakes) and the eccentricity goes
>>> away.
>> bullshit. that caliper [d-a 7700, non-orbital pads] is straight off a
>> bike. the pads are exactly as they were when operating on the rim and
>> haven't been touched.
>>
>
> Straight off a bike? In the other thread, you said it was new in box.
>
>>> It's interesting that jim isn't even trying to show a front
>>> brake doing the opposite.
>> what the fuck is up with you idiots? first it doesn't happen. then
>> it's "optical tricks". now, you want me to strip my bike down again
>> because the evidence that supports what i've been saying all along
>> somehow needs to be re-presented? strip your own fucking bike, examine
>> your own fucking caliper and take your own fucking pics.
>
>
> Pictures like these?
> http://s223.photobucket.com/albums/dd171/unforgiven99/?action=view¤t=Presentation1.jpg
> That's an RX100 front dual pivot, 1990 or so vintage, but the bushings
> are all snug.
>
> The top row shows progressive toe in, but with the pads pointing up
> from horizontal. In other words exactly how the wouldn't be on the
> bike.
> Row two, the caliper was set up with the pads pointing just a little
> bit farther down from horizontal than they would be in operation, and
> the result is a noticeable progression to toe out.
> The pads are non-orbital, and there is no appearance of fore-aft
> translation in either position.
>
> Now, you can call names all you want, but it doesn't make anything
> that you've said or shown us evidence of front/rear non-
> interchangeability. I'll let you back up, split some hairs, and claim
> that Shimano changed their design for dual pivots between my old RX100
> and your new Dura-Ace. I'll even accept it if you can figure out a
> way to prove that the second pivot on your brake is off axis with the
> mounting bolt, but I will not take pictures of brake pads as
> evidence. They don't prove anything.
>
but your caliper still shows toe progression!!! compare with single
pivot!!!
[kinda speechless.]
|
| | | |
Date: 10 Nov 2007 20:39:58
From: Luns Tee
Subject: Re: dual pivot brake caliper toe progression
|
In article <4tOdnQOIK5p9IKjanZ2dnUVZ_urinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
>> Now, you can call names all you want, but it doesn't make anything
>> that you've said or shown us evidence of front/rear non-
>> interchangeability. I'll let you back up, split some hairs, and claim
>> that Shimano changed their design for dual pivots between my old RX100
>> and your new Dura-Ace. I'll even accept it if you can figure out a
>> way to prove that the second pivot on your brake is off axis with the
>> mounting bolt, but I will not take pictures of brake pads as
>> evidence. They don't prove anything.
>>
>
>but your caliper still shows toe progression!!!
These photos show quite clearly that the same front caliper can
have toe-in or toe-out as the caliper closes with just the change of the
pad angle. This is not a function of front calipers being different from
rear calipers as you've claimed, it's a matter of the pads being
mounted at different angles in either application.
>compare with single pivot!!!
No difference.
http://www.OCF.Berkeley.EDU/~tee/rbt/toe/DSC01855.JPG
http://www.OCF.Berkeley.EDU/~tee/rbt/toe/DSC01851.JPG
The phenomenon is weaker for single pivot calipers, but still
exists, and functions as I described it previously. What accentuates
it for dual pivot calipers is that the offset pivot is lower, making a
larger relative difference in the radiii on which the front and back
ends of the pads pivot.
-Luns
|
| | | | |
Date: 10 Nov 2007 23:08:51
From: Luns Tee
Subject: Re: dual pivot brake caliper toe progression
|
In article <fh54uu$mbo$1@agate.berkeley.edu >,
Luns Tee <luns@mochi.EECS.Berkeley.EDU > wrote:
>http://www.OCF.Berkeley.EDU/~tee/rbt/toe/DSC01855.JPG
>http://www.OCF.Berkeley.EDU/~tee/rbt/toe/DSC01851.JPG
Let's try that again (server disk space issues are annoying!).
http://tinyurl.com/yuvm23
http://tinyurl.com/2d3bcg
-Luns
|
| | | | | |
Date: 10 Nov 2007 23:21:09
From: Luns Tee
Subject: Re: dual pivot brake caliper toe progression
|
One more while I'm at it:
http://tinyurl.com/yobozb
This is the same single-pivot Shimano 600EX caliper in my previous
photos.
The lines drawn show the angle of the pads relative to the
pivots as installed on the rear of a bike. The toe of the brake pads is
clearly closer to the pivot axis than the rear. Thus, the toe of the
brake pads move less than the heels do as the caliper is actuated.
-Luns
|
| |
Date: 09 Nov 2007 20:20:46
From: jim beam
Subject: Re: dual pivot brake caliper toe progression
|
jim beam wrote:
> for the skeptics.
>
> http://www.flickr.com/photos/38636024@N00/1928128941/
> http://www.flickr.com/photos/38636024@N00/1928128939/
> http://www.flickr.com/photos/38636024@N00/1928128923/
based on viewer stats, it seems some people are only looking at the
first link. you'll need to look at all three to see the progression.
|
| | |
Date: 10 Nov 2007 09:58:51
From: A Muzi
Subject: Re: dual pivot brake caliper toe progression
|
jim beam wrote:
> jim beam wrote:
>> for the skeptics.
>>
>> http://www.flickr.com/photos/38636024@N00/1928128941/
>> http://www.flickr.com/photos/38636024@N00/1928128939/
>> http://www.flickr.com/photos/38636024@N00/1928128923/
>
> based on viewer stats, it seems some people are only looking at the
> first link. you'll need to look at all three to see the progression.
I saw a photo series of a rear caliper whose shoes ended up angled the
wrong way at full compression. I'm sorry I can't help with that.
Brakes on bicycles here seem to not have any complex mechanism to do
such a complex movement - all DPs here have a pair of simple sleeve
pivots for the arms. Modern shoes have orbital mounts for toeing.
In fact if our rear calipers on bikes moved like your rear brake photos,
we would know it. The pads would be noisy, hitting the rim backwards.
Again, perplexing photos which I don't understand and cannot explain. If
you find no solution, check with Shimano or get some genuine Campagnolo
calipers.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | |
Date: 10 Nov 2007 12:21:01
From: Tim McNamara
Subject: Re: dual pivot brake caliper toe progression
|
A Muzi wrote:
> jim beam wrote:
>> jim beam wrote:
>>> for the skeptics.
>>>
>>> http://www.flickr.com/photos/38636024@N00/1928128941/
>>> http://www.flickr.com/photos/38636024@N00/1928128939/
>>> http://www.flickr.com/photos/38636024@N00/1928128923/
>>
>> based on viewer stats, it seems some people are only looking at the
>> first link. you'll need to look at all three to see the
>> progression.
>
> I saw a photo series of a rear caliper whose shoes ended up angled
> the wrong way at full compression. I'm sorry I can't help with that.
>
> Brakes on bicycles here seem to not have any complex mechanism to do
> such a complex movement - all DPs here have a pair of simple sleeve
> pivots for the arms. Modern shoes have orbital mounts for toeing.
>
> In fact if our rear calipers on bikes moved like your rear brake
> photos, we would know it. The pads would be noisy, hitting the rim
> backwards.
>
> Again, perplexing photos which I don't understand and cannot explain.
> If you find no solution, check with Shimano or get some genuine
> Campagnolo calipers.
I can think of a couple of possibilities to explain the apparent motion.
One is motion parallax error caused by the camera position. Another
is that the brakes are laying freely on a surface and may move slightly
as the brakes close. Note that there are two sets of photos that appear
to show contradictory evidence. Hence my suggestion that the brakes
should be mounted to a planar surface to provide a reference. If I
owned a dual pivot brake, I'd do it, but unfortunately all my bikes have
cantilevers, single pivots or hub brakes.
|
| |
Date: 09 Nov 2007 14:35:16
From: Ozark Bicycle
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 1:08 pm, D'ohBoy <peteng...@yahoo.com > wrote:
> On Nov 9, 11:33 am, Ozark Bicycle
>
>
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Nov 9, 11:18 am, D'ohBoy <peteng...@yahoo.com> wrote:
>
> > > On Nov 9, 10:11 am, Ozark Bicycle
>
> > > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > > On Nov 9, 9:45 am, unforgive...@juno.com wrote:
>
> > > > > On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>
> > > > > > unforgive...@juno.com wrote:
> > > > > > > On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> > > > > > >> for the skeptics.
>
> > > > > > >>http://www.flickr.com/photos/38636024@N00/1928128941/
>
> > > > > > >>http://www.flickr.com/photos/38636024@N00/1928128939/
>
> > > > > > >>http://www.flickr.com/photos/38636024@N00/1928128923/
>
> > > > > > > What about a picture from the side? If the pads aren't parallel to
> > > > > > > the mounting bolt, this proves absolutely nothing.
>
> > > > > > It's difficult to tell from the photos, but it appears that there is an
> > > > > > eccentric motion to the pad on the right. As the brake closes, the
> > > > > > right pad not only moves towards the other pad but also forward (down,
> > > > > > in the photo). This could be explained by the pivots not being parallel
> > > > > > to each other.
>
> > > > > That's the great thing about orbital pad adjustment. You can make it
> > > > > look like all kinds of neat things are happening if you only took at
> > > > > the brake from one direction. Square the pads up like they would be
> > > > > on a bike (where some of us use our brakes) and the eccentricity goes
> > > > > away. It's interesting that jim isn't even trying to show a front
> > > > > brake doing the opposite.
>
> > > > Are you taking the position that jb is deliberately lying? IMO, he
> > > > believes his position is correct. I haven't taken the time to
> > > > 'measure' both a front and rear Shimano or Campy set of dual pivots,
> > > > so I can't say yay or nay. But I do doubt he is willfully being
> > > > deceptive about this.
>
> > > His level of animosity toward those who disagree with him is not
> > > inconsistent with such behavior (willful lying to support incorrect
> > > assertions).
>
> > IMO, much of jb's animosity is a reaction to the animosity displayed
> > *toward* him. And that animosity springs from the fact that he has the
> > temerity to dispute the pronouncements of Jobst the Great and Mighty,
> > who has most people here cowed like a bunch of shit-eating sheep.
>
> I am neither in nor out of either camp.
Did I imply you were?
> And I didn't say he *DID*
> lie.
Not explicitly, no.
And don't look now, but your bias is showing.
>
A bias of having had more than a full dose of Jobst the Great and
Mighty? You bet!!
|
| |
Date: 09 Nov 2007 11:08:00
From: D'ohBoy
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 11:33 am, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> On Nov 9, 11:18 am, D'ohBoy <peteng...@yahoo.com> wrote:
>
>
>
> > On Nov 9, 10:11 am, Ozark Bicycle
>
> > <bicycleatel...@ozarkbicycleservice.com> wrote:
> > > On Nov 9, 9:45 am, unforgive...@juno.com wrote:
>
> > > > On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>
> > > > > unforgive...@juno.com wrote:
> > > > > > On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> > > > > >> for the skeptics.
>
> > > > > >>http://www.flickr.com/photos/38636024@N00/1928128941/
>
> > > > > >>http://www.flickr.com/photos/38636024@N00/1928128939/
>
> > > > > >>http://www.flickr.com/photos/38636024@N00/1928128923/
>
> > > > > > What about a picture from the side? If the pads aren't parallel to
> > > > > > the mounting bolt, this proves absolutely nothing.
>
> > > > > It's difficult to tell from the photos, but it appears that there is an
> > > > > eccentric motion to the pad on the right. As the brake closes, the
> > > > > right pad not only moves towards the other pad but also forward (down,
> > > > > in the photo). This could be explained by the pivots not being parallel
> > > > > to each other.
>
> > > > That's the great thing about orbital pad adjustment. You can make it
> > > > look like all kinds of neat things are happening if you only took at
> > > > the brake from one direction. Square the pads up like they would be
> > > > on a bike (where some of us use our brakes) and the eccentricity goes
> > > > away. It's interesting that jim isn't even trying to show a front
> > > > brake doing the opposite.
>
> > > Are you taking the position that jb is deliberately lying? IMO, he
> > > believes his position is correct. I haven't taken the time to
> > > 'measure' both a front and rear Shimano or Campy set of dual pivots,
> > > so I can't say yay or nay. But I do doubt he is willfully being
> > > deceptive about this.
>
> > His level of animosity toward those who disagree with him is not
> > inconsistent with such behavior (willful lying to support incorrect
> > assertions).
>
> IMO, much of jb's animosity is a reaction to the animosity displayed
> *toward* him. And that animosity springs from the fact that he has the
> temerity to dispute the pronouncements of Jobst the Great and Mighty,
> who has most people here cowed like a bunch of shit-eating sheep.
I am neither in nor out of either camp. And I didn't say he *DID*
lie. And don't look now, but your bias is showing.
D'ohBoy
|
| |
Date: 09 Nov 2007 09:33:16
From: Ozark Bicycle
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 11:18 am, D'ohBoy <peteng...@yahoo.com > wrote:
> On Nov 9, 10:11 am, Ozark Bicycle
>
>
>
> <bicycleatel...@ozarkbicycleservice.com> wrote:
> > On Nov 9, 9:45 am, unforgive...@juno.com wrote:
>
> > > On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>
> > > > unforgive...@juno.com wrote:
> > > > > On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> > > > >> for the skeptics.
>
> > > > >>http://www.flickr.com/photos/38636024@N00/1928128941/
>
> > > > >>http://www.flickr.com/photos/38636024@N00/1928128939/
>
> > > > >>http://www.flickr.com/photos/38636024@N00/1928128923/
>
> > > > > What about a picture from the side? If the pads aren't parallel to
> > > > > the mounting bolt, this proves absolutely nothing.
>
> > > > It's difficult to tell from the photos, but it appears that there is an
> > > > eccentric motion to the pad on the right. As the brake closes, the
> > > > right pad not only moves towards the other pad but also forward (down,
> > > > in the photo). This could be explained by the pivots not being parallel
> > > > to each other.
>
> > > That's the great thing about orbital pad adjustment. You can make it
> > > look like all kinds of neat things are happening if you only took at
> > > the brake from one direction. Square the pads up like they would be
> > > on a bike (where some of us use our brakes) and the eccentricity goes
> > > away. It's interesting that jim isn't even trying to show a front
> > > brake doing the opposite.
>
> > Are you taking the position that jb is deliberately lying? IMO, he
> > believes his position is correct. I haven't taken the time to
> > 'measure' both a front and rear Shimano or Campy set of dual pivots,
> > so I can't say yay or nay. But I do doubt he is willfully being
> > deceptive about this.
>
> His level of animosity toward those who disagree with him is not
> inconsistent with such behavior (willful lying to support incorrect
> assertions).
>
IMO, much of jb's animosity is a reaction to the animosity displayed
*toward* him. And that animosity springs from the fact that he has the
temerity to dispute the pronouncements of Jobst the Great and Mighty,
who has most people here cowed like a bunch of shit-eating sheep.
|
| | |
Date: 10 Nov 2007 06:40:24
From: Tom Sherman
Subject: Re: dual pivot brake caliper toe progression
|
Ozark Bicycle wrote:
> On Nov 9, 11:18 am, D'ohBoy <peteng...@yahoo.com> wrote:
>> On Nov 9, 10:11 am, Ozark Bicycle
>>
>> <bicycleatel...@ozarkbicycleservice.com> wrote:
>>> On Nov 9, 9:45 am, unforgive...@juno.com wrote:
>>>> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>>>>> unforgive...@juno.com wrote:
>>>>>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>>>> for the skeptics.
>>>>>>> http://www.flickr.com/photos/38636024@N00/1928128941/
>>>>>>> http://www.flickr.com/photos/38636024@N00/1928128939/
>>>>>>> http://www.flickr.com/photos/38636024@N00/1928128923/
>>>>>> What about a picture from the side? If the pads aren't parallel to
>>>>>> the mounting bolt, this proves absolutely nothing.
>>>>> It's difficult to tell from the photos, but it appears that there is an
>>>>> eccentric motion to the pad on the right. As the brake closes, the
>>>>> right pad not only moves towards the other pad but also forward (down,
>>>>> in the photo). This could be explained by the pivots not being parallel
>>>>> to each other.
>>>> That's the great thing about orbital pad adjustment. You can make it
>>>> look like all kinds of neat things are happening if you only took at
>>>> the brake from one direction. Square the pads up like they would be
>>>> on a bike (where some of us use our brakes) and the eccentricity goes
>>>> away. It's interesting that jim isn't even trying to show a front
>>>> brake doing the opposite.
>>> Are you taking the position that jb is deliberately lying? IMO, he
>>> believes his position is correct. I haven't taken the time to
>>> 'measure' both a front and rear Shimano or Campy set of dual pivots,
>>> so I can't say yay or nay. But I do doubt he is willfully being
>>> deceptive about this.
>> His level of animosity toward those who disagree with him is not
>> inconsistent with such behavior (willful lying to support incorrect
>> assertions).
>
> IMO, much of jb's animosity is a reaction to the animosity displayed
> *toward* him. And that animosity springs from the fact that he has the
> temerity to dispute the pronouncements of Jobst the Great and Mighty,
> who has most people here cowed like a bunch of shit-eating sheep.
>
Your jealousy is showing again.
--
Tom Sherman - Holstein-Friesland Bovinia
Tradition is the worst rational for action.
|
| |
Date: 09 Nov 2007 09:18:52
From: D'ohBoy
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 10:11 am, Ozark Bicycle
<bicycleatel...@ozarkbicycleservice.com > wrote:
> On Nov 9, 9:45 am, unforgive...@juno.com wrote:
>
>
>
> > On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>
> > > unforgive...@juno.com wrote:
> > > > On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> > > >> for the skeptics.
>
> > > >>http://www.flickr.com/photos/38636024@N00/1928128941/
>
> > > >>http://www.flickr.com/photos/38636024@N00/1928128939/
>
> > > >>http://www.flickr.com/photos/38636024@N00/1928128923/
>
> > > > What about a picture from the side? If the pads aren't parallel to
> > > > the mounting bolt, this proves absolutely nothing.
>
> > > It's difficult to tell from the photos, but it appears that there is an
> > > eccentric motion to the pad on the right. As the brake closes, the
> > > right pad not only moves towards the other pad but also forward (down,
> > > in the photo). This could be explained by the pivots not being parallel
> > > to each other.
>
> > That's the great thing about orbital pad adjustment. You can make it
> > look like all kinds of neat things are happening if you only took at
> > the brake from one direction. Square the pads up like they would be
> > on a bike (where some of us use our brakes) and the eccentricity goes
> > away. It's interesting that jim isn't even trying to show a front
> > brake doing the opposite.
>
> Are you taking the position that jb is deliberately lying? IMO, he
> believes his position is correct. I haven't taken the time to
> 'measure' both a front and rear Shimano or Campy set of dual pivots,
> so I can't say yay or nay. But I do doubt he is willfully being
> deceptive about this.
His level of animosity toward those who disagree with him is not
inconsistent with such behavior (willful lying to support incorrect
assertions).
D'ohBoy
|
| |
Date: 09 Nov 2007 08:11:51
From: Ozark Bicycle
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 9:45 am, unforgive...@juno.com wrote:
> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>
>
>
> > unforgive...@juno.com wrote:
> > > On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> > >> for the skeptics.
>
> > >>http://www.flickr.com/photos/38636024@N00/1928128941/
>
> > >>http://www.flickr.com/photos/38636024@N00/1928128939/
>
> > >>http://www.flickr.com/photos/38636024@N00/1928128923/
>
> > > What about a picture from the side? If the pads aren't parallel to
> > > the mounting bolt, this proves absolutely nothing.
>
> > It's difficult to tell from the photos, but it appears that there is an
> > eccentric motion to the pad on the right. As the brake closes, the
> > right pad not only moves towards the other pad but also forward (down,
> > in the photo). This could be explained by the pivots not being parallel
> > to each other.
>
> That's the great thing about orbital pad adjustment. You can make it
> look like all kinds of neat things are happening if you only took at
> the brake from one direction. Square the pads up like they would be
> on a bike (where some of us use our brakes) and the eccentricity goes
> away. It's interesting that jim isn't even trying to show a front
> brake doing the opposite.
Are you taking the position that jb is deliberately lying? IMO, he
believes his position is correct. I haven't taken the time to
'measure' both a front and rear Shimano or Campy set of dual pivots,
so I can't say yay or nay. But I do doubt he is willfully being
deceptive about this.
|
| |
Date: 09 Nov 2007 07:45:33
From:
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net > wrote:
> unforgive...@juno.com wrote:
> > On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> >> for the skeptics.
>
> >>http://www.flickr.com/photos/38636024@N00/1928128941/
>
> >>http://www.flickr.com/photos/38636024@N00/1928128939/
>
> >>http://www.flickr.com/photos/38636024@N00/1928128923/
>
> > What about a picture from the side? If the pads aren't parallel to
> > the mounting bolt, this proves absolutely nothing.
>
> It's difficult to tell from the photos, but it appears that there is an
> eccentric motion to the pad on the right. As the brake closes, the
> right pad not only moves towards the other pad but also forward (down,
> in the photo). This could be explained by the pivots not being parallel
> to each other.
That's the great thing about orbital pad adjustment. You can make it
look like all kinds of neat things are happening if you only took at
the brake from one direction. Square the pads up like they would be
on a bike (where some of us use our brakes) and the eccentricity goes
away. It's interesting that jim isn't even trying to show a front
brake doing the opposite.
|
| | |
Date: 09 Nov 2007 19:49:29
From: jim beam
Subject: Re: dual pivot brake caliper toe progression
|
unforgiven99@juno.com wrote:
> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>> unforgive...@juno.com wrote:
>>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
>>>> for the skeptics.
>>>> http://www.flickr.com/photos/38636024@N00/1928128941/
>>>> http://www.flickr.com/photos/38636024@N00/1928128939/
>>>> http://www.flickr.com/photos/38636024@N00/1928128923/
>>> What about a picture from the side? If the pads aren't parallel to
>>> the mounting bolt, this proves absolutely nothing.
>> It's difficult to tell from the photos, but it appears that there is an
>> eccentric motion to the pad on the right. As the brake closes, the
>> right pad not only moves towards the other pad but also forward (down,
>> in the photo). This could be explained by the pivots not being parallel
>> to each other.
>
> That's the great thing about orbital pad adjustment. You can make it
> look like all kinds of neat things are happening if you only took at
> the brake from one direction. Square the pads up like they would be
> on a bike (where some of us use our brakes) and the eccentricity goes
> away.
bullshit. that caliper [d-a 7700, non-orbital pads] is straight off a
bike. the pads are exactly as they were when operating on the rim and
haven't been touched.
> It's interesting that jim isn't even trying to show a front
> brake doing the opposite.
what the fuck is up with you idiots? first it doesn't happen. then
it's "optical tricks". now, you want me to strip my bike down again
because the evidence that supports what i've been saying all along
somehow needs to be re-presented? strip your own fucking bike, examine
your own fucking caliper and take your own fucking pics.
|
| | | |
Date: 10 Nov 2007 06:48:45
From: Tom Sherman
Subject: Re: dual pivot brake caliper toe progression
|
"jim beam" wrote:
> ...
> what the fuck is up with you idiots? first it doesn't happen. then
> it's "optical tricks". now, you want me to strip my bike down again
> because the evidence that supports what i've been saying all along
> somehow needs to be re-presented? strip your own fucking bike, examine
> your own fucking caliper and take your own fucking pics.
>
Ain't "jimmy" cute when he gets mad?
By the way, this is not the "sex with bicycle" thread.
--
Tom Sherman - Holstein-Friesland Bovinia
Tradition is the worst rational for action.
|
| | | | |
Date: 10 Nov 2007 06:18:56
From: jim beam
Subject: Re: dual pivot brake caliper toe progression
|
Tom Sherman wrote:
> "jim beam" wrote:
>> ...
>> what the fuck is up with you idiots? first it doesn't happen. then
>> it's "optical tricks". now, you want me to strip my bike down again
>> because the evidence that supports what i've been saying all along
>> somehow needs to be re-presented? strip your own fucking bike,
>> examine your own fucking caliper and take your own fucking pics.
>>
> Ain't "jimmy" cute when he gets mad?
>
> By the way, this is not the "sex with bicycle" thread.
>
"Children with AS ... have difficulty understanding metaphorical
language and tend to use language literally. Individuals with AS appear
to have particular weaknesses in areas of nonliteral language that
include humor, irony, and teasing."
http://en.wikipedia.org/wiki/Asperger_syndrome
your consistent literalism in such a context is highly symptomatic.
|
| | | | | |
Date: 10 Nov 2007 10:08:42
From: Tom Sherman
Subject: Re: dual pivot brake caliper toe progression
|
"jim beam" wrote:
> Tom Sherman wrote:
>> "jim beam" wrote:
>>> ...
>>> what the fuck is up with you idiots? first it doesn't happen. then
>>> it's "optical tricks". now, you want me to strip my bike down again
>>> because the evidence that supports what i've been saying all along
>>> somehow needs to be re-presented? strip your own fucking bike,
>>> examine your own fucking caliper and take your own fucking pics.
>>>
>> Ain't "jimmy" cute when he gets mad?
>>
>> By the way, this is not the "sex with bicycle" thread.
>>
>
> "Children with AS ... have difficulty understanding metaphorical
> language and tend to use language literally. Individuals with AS appear
> to have particular weaknesses in areas of nonliteral language that
> include humor, irony, and teasing."
>
> http://en.wikipedia.org/wiki/Asperger_syndrome
>
> your consistent literalism in such a context is highly symptomatic.
Yet here, "jim" misses the point that the literalism IS the joke.
--
Tom Sherman - Holstein-Friesland Bovinia
Tradition is the worst rational for action.
|
| | |
Date: 09 Nov 2007 12:05:46
From: Tim McNamara
Subject: Re: dual pivot brake caliper toe progression
|
unforgiven99@juno.com wrote:
> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
>
>> unforgive...@juno.com wrote:
>>
>>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
>>>
>>>> for the skeptics.
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/1928128941/
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/1928128939/
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/1928128923/
>>>>
>>> What about a picture from the side? If the pads aren't parallel
>>> to the mounting bolt, this proves absolutely nothing.
>>
>> It's difficult to tell from the photos, but it appears that there
>> is an eccentric motion to the pad on the right. As the brake
>> closes, the right pad not only moves towards the other pad but also
>> forward (down, in the photo). This could be explained by the
>> pivots not being parallel to each other.
>
> That's the great thing about orbital pad adjustment. You can make it
> look like all kinds of neat things are happening if you only took at
> the brake from one direction. Square the pads up like they would be
> on a bike (where some of us use our brakes) and the eccentricity
> goes away. It's interesting that jim isn't even trying to show a
> front brake doing the opposite.
Far be it from me to accept anything from "jim beam" at face value,
however I am not at all certain that the orientation of the pad would
produce the apparent effect shown in the photos. The apparent movement
is about 1/8". The sweep of the ends of the pads would be the same
regardless of their orientation.
The problem with the photo is that the brake is lying on an open book
rather than mounted firmly. If "jim beam" really wants to demonstrate
his point, he'd do better to mount the brake on a flat surface (e.g.,
drill a mounting hole through a board and mount the brake to it), which
would provide a plane reference surface against which to judge the
movement. I don't own a dual pivot brake or I'd do it myself.
Unfortunately, "jim beam" won't accept my suggestion simply because it
comes from me, so the point will remain moot.
If the eccentric motion is real, the likelier explanation is that the
pivot axes are not parallel.
(And what's up with Google Groups's removal of newlines from quoted
material? What a pain in the ass to have to keep fixing. That's 90%
of the legibility problem in these long threads. Google must fear the
whitespace. Jeez, I wish people would use real newsreaders.)
|
| | | |
Date: 10 Nov 2007 06:46:06
From: Tom Sherman
Subject: Re: dual pivot brake caliper toe progression
|
Tim McNamara wrote:
> ...
> The problem with the photo is that the brake is lying on an open book
> rather than mounted firmly. If "jim beam" really wants to demonstrate
> his point, he'd do better to mount the brake on a flat surface (e.g.,
> drill a mounting hole through a board and mount the brake to it), which
> would provide a plane reference surface against which to judge the
> movement. I don't own a dual pivot brake or I'd do it myself.
> Unfortunately, "jim beam" won't accept my suggestion simply because it
> comes from me, so the point will remain moot....
do it yourself, lightweight. ;)
--
Tom Sherman - Holstein-Friesland Bovinia
Tradition is the worst rational for action.
|
| | | | |
Date: 10 Nov 2007 12:14:37
From: Tim McNamara
Subject: Re: dual pivot brake caliper toe progression
|
Tom Sherman wrote:
> Tim McNamara wrote:
>> ...
>> The problem with the photo is that the brake is lying on an open book
>> rather than mounted firmly. If "jim beam" really wants to demonstrate
>> his point, he'd do better to mount the brake on a flat surface (e.g.,
>> drill a mounting hole through a board and mount the brake to it),
>> which would provide a plane reference surface against which to judge
>> the movement. I don't own a dual pivot brake or I'd do it myself.
>> Unfortunately, "jim beam" won't accept my suggestion simply because it
>> comes from me, so the point will remain moot....
>
> do it yourself, lightweight. ;)
No, no. Get it straight. You're the lightweight. I'm the retard.
Krygowski's the idiot. Jobst is satan in "jim's" little world, as far
as I can tell. I can't remember the rest of "jim's" little pet names.
|
| | | | | |
Date: 11 Nov 2007 00:45:15
From: Andrew Price
Subject: Re: dual pivot brake caliper toe progression
|
On Sat, 10 Nov 2007 12:14:37 -0600, Tim McNamara
<timmcn@bitstream.net > wrote:
>No, no. Get it straight. You're the lightweight. I'm the retard.
>Krygowski's the idiot. Jobst is satan in "jim's" little world, as far
>as I can tell. I can't remember the rest of "jim's" little pet names.
He seems to use "moron" on a fairly regular basis.
|
| | | | | | |
Date: 11 Nov 2007 11:17:28
From: Tom Sherman
Subject: Re: dual pivot brake caliper toe progression
|
Andrew Price wrote:
> On Sat, 10 Nov 2007 12:14:37 -0600, Tim McNamara
> <timmcn@bitstream.net> wrote:
>
>> No, no. Get it straight. You're the lightweight. I'm the retard.
>> Krygowski's the idiot. Jobst is satan in "jim's" little world, as far
>> as I can tell. I can't remember the rest of "jim's" little pet names.
>
> He seems to use "moron" on a fairly regular basis.
I wonder if "jim" would be so free with the insults if he/she/it had to
use his/her/its real name? (Of course, that never stopped Mr. Ed the Grate.)
--
Tom Sherman - Holstein-Friesland Bovinia
Tradition is the worst rational for action.
|
| | | |
Date: 09 Nov 2007 19:50:21
From: jim beam
Subject: Re: dual pivot brake caliper toe progression
|
Tim McNamara wrote:
> unforgiven99@juno.com wrote:
>
>> On Nov 9, 10:22 am, Tim McNamara <tim...@bitstream.net> wrote:
> >
>>> unforgive...@juno.com wrote:
> >>
>>>> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
> >>>
>>>>> for the skeptics.
> >>>>
>>>>> http://www.flickr.com/photos/38636024@N00/1928128941/
> >>>>
>>>>> http://www.flickr.com/photos/38636024@N00/1928128939/
> >>>>
>>>>> http://www.flickr.com/photos/38636024@N00/1928128923/
> >>>>
>>>> What about a picture from the side? If the pads aren't parallel
>>>> to the mounting bolt, this proves absolutely nothing.
> >>
>>> It's difficult to tell from the photos, but it appears that there
>>> is an eccentric motion to the pad on the right. As the brake
>>> closes, the right pad not only moves towards the other pad but also
>>> forward (down, in the photo). This could be explained by the
>>> pivots not being parallel to each other.
>>
>> That's the great thing about orbital pad adjustment. You can make it
>> look like all kinds of neat things are happening if you only took at
>> the brake from one direction. Square the pads up like they would be
>> on a bike (where some of us use our brakes) and the eccentricity
>> goes away. It's interesting that jim isn't even trying to show a
>> front brake doing the opposite.
>
> Far be it from me to accept anything from "jim beam" at face value,
> however I am not at all certain that the orientation of the pad would
> produce the apparent effect shown in the photos. The apparent movement
> is about 1/8". The sweep of the ends of the pads would be the same
> regardless of their orientation.
correct.
>
> The problem with the photo is that the brake is lying on an open book
> rather than mounted firmly. If "jim beam" really wants to demonstrate
> his point, he'd do better to mount the brake on a flat surface (e.g.,
> drill a mounting hole through a board and mount the brake to it), which
> would provide a plane reference surface against which to judge the
> movement.
doesn't make any difference - study the pads, not the paper.
> I don't own a dual pivot brake or I'd do it myself.
evidently the same situation as the other posters!
> Unfortunately, "jim beam" won't accept my suggestion simply because it
> comes from me, so the point will remain moot.
i'd do it if it was relevant, but you're barking up the wrong tree.
>
> If the eccentric motion is real, the likelier explanation is that the
> pivot axes are not parallel.
indeed. it's really not hard if one thinks about it.
>
> (And what's up with Google Groups's removal of newlines from quoted
> material? What a pain in the ass to have to keep fixing. That's 90%
> of the legibility problem in these long threads. Google must fear the
> whitespace. Jeez, I wish people would use real newsreaders.)
|
| |
Date: 09 Nov 2007 06:42:16
From:
Subject: Re: dual pivot brake caliper toe progression
|
On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net > wrote:
> for the skeptics.
>
> http://www.flickr.com/photos/38636024@N00/1928128941/http://www.flickr.com/photos/38636024@N00/1928128939/http://www.flickr.com/photos/38636024@N00/1928128923/
What about a picture from the side? If the pads aren't parallel to
the mounting bolt, this proves absolutely nothing.
|
| | |
Date: 09 Nov 2007 09:22:25
From: Tim McNamara
Subject: Re: dual pivot brake caliper toe progression
|
unforgiven99@juno.com wrote:
> On Nov 9, 12:47 am, jim beam <spamvor...@bad.example.net> wrote:
>> for the skeptics.
>>
>> http://www.flickr.com/photos/38636024@N00/1928128941/
>>
>> http://www.flickr.com/photos/38636024@N00/1928128939/
>>
>> http://www.flickr.com/photos/38636024@N00/1928128923/
>
> What about a picture from the side? If the pads aren't parallel to
> the mounting bolt, this proves absolutely nothing.
It's difficult to tell from the photos, but it appears that there is an
eccentric motion to the pad on the right. As the brake closes, the
right pad not only moves towards the other pad but also forward (down,
in the photo). This could be explained by the pivots not being parallel
to each other.
|
| | | |
Date: 09 Nov 2007 18:04:06
From: Luns Tee
Subject: Re: dual pivot brake caliper toe progression
|
In article <47347b2f$0$19227$8046368a@newsreader.iphouse.net >,
Tim McNamara <timmcn@bitstream.net > wrote:
>It's difficult to tell from the photos, but it appears that there is an
>eccentric motion to the pad on the right. As the brake closes, the
>right pad not only moves towards the other pad but also forward (down,
>in the photo). This could be explained by the pivots not being parallel
>to each other.
It's not a matter of the pivots: the same thing happens with
single-pivot brakes with both brake arms pivoting on the same bolt.
This is a matter of the brake pads not being parallel to the
brake pivots. A rear brake has its pads mounted with their rear end
farther from the pivots than the front end. Being at a larger radius
from the pivot, the rear end moves more than the front. A front brake,
thanks to the offset off the fork, has its pads more parallel to its
pivot.
It's a stretch of the imagination to to think that this is a
deliberate effect though. More to the point of what started this
discussion, a front brake mounted on the rear has its pads at the same
angle relative to its pivots as a rear brake mounted on the rear.
-Luns
|
| | | | |
Date: 09 Nov 2007 19:51:50
From: jim beam
Subject: Re: dual pivot brake caliper toe progression
|
Luns Tee wrote:
> In article <47347b2f$0$19227$8046368a@newsreader.iphouse.net>,
> Tim McNamara <timmcn@bitstream.net> wrote:
>> It's difficult to tell from the photos, but it appears that there is an
>> eccentric motion to the pad on the right. As the brake closes, the
>> right pad not only moves towards the other pad but also forward (down,
>> in the photo). This could be explained by the pivots not being parallel
>> to each other.
>
> It's not a matter of the pivots: the same thing happens with
> single-pivot brakes with both brake arms pivoting on the same bolt.
no it doesn't! you clearly haven't compared the two types. i have.
>
> This is a matter of the brake pads not being parallel to the
> brake pivots.
no it's not. that's something i've already checked.
> A rear brake has its pads mounted with their rear end
> farther from the pivots than the front end.
no, that depends on the frame. and it doesn't change this result.
> Being at a larger radius
> from the pivot, the rear end moves more than the front. A front brake,
> thanks to the offset off the fork, has its pads more parallel to its
> pivot.
distance from the pivots simply changes the length of travel, not the
degree of offset.
>
> It's a stretch of the imagination to to think that this is a
> deliberate effect though.
why? toe is well known to address squeal and offer modulation.
> More to the point of what started this
> discussion, a front brake mounted on the rear has its pads at the same
> angle relative to its pivots as a rear brake mounted on the rear.
but the pivots are not set at the same angles!
|
| | | | |
Date: 09 Nov 2007 18:33:56
From: Tim McNamara
Subject: Re: dual pivot brake caliper toe progression
|
Luns Tee wrote:
> In article <47347b2f$0$19227$8046368a@newsreader.iphouse.net>, Tim
> McNamara <timmcn@bitstream.net> wrote:
>
>> It's difficult to tell from the photos, but it appears that there
>> is an eccentric motion to the pad on the right. As the brake
>> closes, the right pad not only moves towards the other pad but also
>> forward (down, in the photo). This could be explained by the
>> pivots not being parallel to each other.
>
> It's not a matter of the pivots: the same thing happens with
> single-pivot brakes with both brake arms pivoting on the same bolt.
>
> This is a matter of the brake pads not being parallel to the brake
> pivots. A rear brake has its pads mounted with their rear end farther
> from the pivots than the front end. Being at a larger radius from the
> pivot, the rear end moves more than the front. A front brake, thanks
> to the offset off the fork, has its pads more parallel to its pivot.
That doesn't suffice to explain the apparent movement shown in "jim's"
photos in which one pad appears to move forward relative to the other.
That could just be an artifact of the brake laying on an open book,
hence my suggestion to "jim" to mount the brake on a planar surface to
provide a reference.
> It's a stretch of the imagination to to think that this is a
> deliberate effect though. More to the point of what started this
> discussion, a front brake mounted on the rear has its pads at the
> same angle relative to its pivots as a rear brake mounted on the
> rear.
Calipers can be swapped front for back and always have been
interchangeable; the only difference is the lengths of the pivot bolts.
Except for the recent Campy arrangement with a dual pivot in front and
a single pivot in the rear, that is.
|
| | | | | |
Date: 10 Nov 2007 20:51:17
From: Luns Tee
Subject: Re: dual pivot brake caliper toe progression
|
In article <4734fc73$0$50266$8046368a@newsreader.iphouse.net >,
Tim McNamara <timmcn@bitstream.net > wrote:
>Luns Tee wrote:
>> In article <47347b2f$0$19227$8046368a@newsreader.iphouse.net>, Tim
>> McNamara <timmcn@bitstream.net> wrote:
> >
>>> It's difficult to tell from the photos, but it appears that there
>>> is an eccentric motion to the pad on the right. As the brake
>>> closes, the right pad not only moves towards the other pad but also
>>> forward (down, in the photo). This could be explained by the
>>> pivots not being parallel to each other.
>>
>> It's not a matter of the pivots: the same thing happens with
>> single-pivot brakes with both brake arms pivoting on the same bolt.
>>
>> This is a matter of the brake pads not being parallel to the brake
>> pivots. A rear brake has its pads mounted with their rear end farther
>> from the pivots than the front end. Being at a larger radius from the
>> pivot, the rear end moves more than the front. A front brake, thanks
>> to the offset off the fork, has its pads more parallel to its pivot.
>
>That doesn't suffice to explain the apparent movement shown in "jim's"
>photos in which one pad appears to move forward relative to the other.
>That could just be an artifact of the brake laying on an open book,
>hence my suggestion to "jim" to mount the brake on a planar surface to
>provide a reference.
I'm sorry, I missed your point on first reading, and wrote
addressing the phenomenon of changing toe.
I think what you're seeing is a combination of foreshortening
and parallax. As the centre-pivot arm closes in on the rim, the pads
move down towards the hub. The offset-pivot arm does the opposite, with
the pivot being outboard of the pad rather than inboard (this is the
cosine effect that Jobst dislikes with these brakes). What this means is
that in the photos, one pad is retreating away from the camera, while
the other gets closer. The movement you're seeing is just the effect of
parallax as you see this motion.
>> It's a stretch of the imagination to to think that this is a
>> deliberate effect though. More to the point of what started this
>> discussion, a front brake mounted on the rear has its pads at the
>> same angle relative to its pivots as a rear brake mounted on the
>> rear.
>
>Calipers can be swapped front for back and always have been
>interchangeable; the only difference is the lengths of the pivot bolts.
Agreed.
-Luns
|
| | | | | |
Date: 09 Nov 2007 19:50:44
From: jim beam
Subject: Re: dual pivot brake caliper toe progression
|
Tim McNamara wrote:
> Luns Tee wrote:
>> In article <47347b2f$0$19227$8046368a@newsreader.iphouse.net>, Tim
>> McNamara <timmcn@bitstream.net> wrote:
> >
>>> It's difficult to tell from the photos, but it appears that there
>>> is an eccentric motion to the pad on the right. As the brake
>>> closes, the right pad not only moves towards the other pad but also
>>> forward (down, in the photo). This could be explained by the
>>> pivots not being parallel to each other.
>>
>> It's not a matter of the pivots: the same thing happens with
>> single-pivot brakes with both brake arms pivoting on the same bolt.
>>
>> This is a matter of the brake pads not being parallel to the brake
>> pivots. A rear brake has its pads mounted with their rear end farther
>> from the pivots than the front end. Being at a larger radius from the
>> pivot, the rear end moves more than the front. A front brake, thanks
>> to the offset off the fork, has its pads more parallel to its pivot.
>
> That doesn't suffice to explain the apparent movement shown in "jim's"
> photos in which one pad appears to move forward relative to the other.
> That could just be an artifact of the brake laying on an open book,
> hence my suggestion to "jim" to mount the brake on a planar surface to
> provide a reference.
irrelevant. look at the pads.
>
>> It's a stretch of the imagination to to think that this is a
>> deliberate effect though. More to the point of what started this
>> discussion, a front brake mounted on the rear has its pads at the
>> same angle relative to its pivots as a rear brake mounted on the
>> rear.
>
> Calipers can be swapped front for back and always have been
> interchangeable; the only difference is the lengths of the pivot bolts.
> Except for the recent Campy arrangement with a dual pivot in front and
> a single pivot in the rear, that is.
single pivot, yes. dual pivot, no. the toe regime is specific to front
and rear. and that's why the manufacturers actually say they're not
interchangeable!
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|
