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Main
Date: 22 Jun 2007 19:40:08
From: kwalters
Subject: Question on rear dropout adjusting screws
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Have an older steel frame with adjusting screws in each dropout.
Just what do these do? Compensate for misaligned dropouts? Allow
the wheelbase to be shortened/lengthened? Both former and latter?
If I take them out, do I weaken the dropouts, since each dropout will
have a hole thru it fore and aft?
Thanks. Ken
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Date: 24 Jun 2007 14:51:39
From: A Muzi
Subject: Re: Question on rear dropout adjusting screws
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kwalters wrote:
> Have an older steel frame with adjusting screws in each dropout.
> Just what do these do? Compensate for misaligned dropouts? Allow
> the wheelbase to be shortened/lengthened? Both former and latter?
>
> If I take them out, do I weaken the dropouts, since each dropout will
> have a hole thru it fore and aft?
Convenience only.
As with the conical springs on your skewer, makes wheel changes a
split-second faster. Throw out the springs and those little screws with
impunity - and save grams!!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 24 Jun 2007 18:27:23
From: * * Chas
Subject: Re: Question on rear dropout adjusting screws
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"A Muzi" <am@yellowjersey.org > wrote in message
news:137tir2hh3p98c7@corp.supernews.com...
> kwalters wrote:
> > Have an older steel frame with adjusting screws in each dropout.
> > Just what do these do? Compensate for misaligned dropouts? Allow
> > the wheelbase to be shortened/lengthened? Both former and latter?
> >
> > If I take them out, do I weaken the dropouts, since each dropout will
> > have a hole thru it fore and aft?
>
> Convenience only.
> As with the conical springs on your skewer, makes wheel changes a
> split-second faster. Throw out the springs and those little screws with
> impunity - and save grams!!
>
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
But they don't look as retro.
Chas.
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Date: 23 Jun 2007 21:05:40
From: Jay Beattie
Subject: Re: Question on rear dropout adjusting screws
|
On Jun 23, 3:32 pm, "* * Chas" <verktygj...@aol.spamski.com > wrote:
> "kwalters" <kwalt...@frii.com> wrote in message
>
> news:137oufskp5vpb6d@corp.supernews.com...
>
> > Have an older steel frame with adjusting screws in each dropout.
> > Just what do these do? Compensate for misaligned dropouts? Allow
> > the wheelbase to be shortened/lengthened? Both former and latter?
>
> > If I take them out, do I weaken the dropouts, since each dropout will
> > have a hole thru it fore and aft?
>
> > Thanks. Ken
>
> As several others have noted, it makes no difference strength wise if you
> have the screws in or not.
>
> The screws serve a number of purposes.
>
> In the late 1980s Shimano set the standard for location of the rear
> derailleur gear hanger bolt hole relative to the hub axle. Prior to that
> there was no standard and this created some problems with index shifting.
>
> One of the first reasons for the adjustment screws was to aid in
> reinstalling rear wheels to quickly position them between the chainstays
> and locate them above the derailleur for the proper chain gap.
>
> A lot of bike frames were pretty crudely made and differences in chainstay
> length of up to a 1/4" (6mm) was not uncommon. On a lot of older
> derailleurs the chain gap - the distance between the jockey pulley and the
> sprockets - was critical for good shifting.
>
> Suntour and later Shimano put adjusting screws on their derailleurs ( the
> "B" dimension that Peter mentioned ) for correcting this distance but
> positioning the wheel forward or back was the only way to adjust the chain
> gap with derailleurs based on Campy's 1960s Record design which many
> makers copied.
<snip >
For me, moving the wheel never made much of a difference in shifting
with the NR derailleur. I just centered it in the dropouts and forgot
about it -- unless I had bad race anxiety and needed more mojo, then I
would shorten the wheel base and convince myself it made a difference.
It had about the same effect as making sure the file tread on my sew-
ups was going the right direction, or that the CG was on the rear and
the CX in front.-- Jay Beattie.
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Date: 24 Jun 2007 11:00:47
From: * * Chas
Subject: Re: Question on rear dropout adjusting screws
|
"Jay Beattie" <jbeattie@lindsayhart.com > wrote in message
news:1182657940.110358.220420@o11g2000prd.googlegroups.com...
> On Jun 23, 3:32 pm, "* * Chas" <verktygj...@aol.spamski.com> wrote:
> > "kwalters" <kwalt...@frii.com> wrote in message
> >
> > news:137oufskp5vpb6d@corp.supernews.com...
> >
> > > Have an older steel frame with adjusting screws in each dropout.
> > > Just what do these do? Compensate for misaligned dropouts? Allow
> > > the wheelbase to be shortened/lengthened? Both former and latter?
> >
> > > If I take them out, do I weaken the dropouts, since each dropout
will
> > > have a hole thru it fore and aft?
> >
> > > Thanks. Ken
> >
> > As several others have noted, it makes no difference strength wise if
you
> > have the screws in or not.
> >
> > The screws serve a number of purposes.
> >
> > In the late 1980s Shimano set the standard for location of the rear
> > derailleur gear hanger bolt hole relative to the hub axle. Prior to
that
> > there was no standard and this created some problems with index
shifting.
> >
> > One of the first reasons for the adjustment screws was to aid in
> > reinstalling rear wheels to quickly position them between the
chainstays
> > and locate them above the derailleur for the proper chain gap.
> >
> > A lot of bike frames were pretty crudely made and differences in
chainstay
> > length of up to a 1/4" (6mm) was not uncommon. On a lot of older
> > derailleurs the chain gap - the distance between the jockey pulley and
the
> > sprockets - was critical for good shifting.
> >
> > Suntour and later Shimano put adjusting screws on their derailleurs
( the
> > "B" dimension that Peter mentioned ) for correcting this distance but
> > positioning the wheel forward or back was the only way to adjust the
chain
> > gap with derailleurs based on Campy's 1960s Record design which many
> > makers copied.
>
> <snip>
>
> For me, moving the wheel never made much of a difference in shifting
> with the NR derailleur. I just centered it in the dropouts and forgot
> about it -- unless I had bad race anxiety and needed more mojo, then I
> would shorten the wheel base and convince myself it made a difference.
> It had about the same effect as making sure the file tread on my sew-
> ups was going the right direction, or that the CG was on the rear and
> the CX in front.-- Jay Beattie.
>
On some bikes it didn't make too much difference. I've seen bikes where
you could increase or decrease the head tube angle by up to 2 degrees by
moving the wheel - 75° for criteriums and 73° for road races. With the
longer 1010a dropouts you can change the wheel base length at least 20mm,
even more with the older 1010 dropouts.
The adjustability being more of a function of dropout length than
adjustment screws.
The notion of adjustable frames came down from the old-time bikies and
framesmiths in the early 1970s. We had several ex-pat Brits in our cycling
group one of whom raced semi-pro in Blighty.
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Date: 24 Jun 2007 03:40:29
From: datakoll
Subject: Re: Question on rear dropout adjusting screws
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Hide quoted text -
LOCTITE?
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Date: 23 Jun 2007 15:32:07
From: * * Chas
Subject: Re: Question on rear dropout adjusting screws
|
"kwalters" <kwalters@frii.com > wrote in message
news:137oufskp5vpb6d@corp.supernews.com...
> Have an older steel frame with adjusting screws in each dropout.
> Just what do these do? Compensate for misaligned dropouts? Allow
> the wheelbase to be shortened/lengthened? Both former and latter?
>
> If I take them out, do I weaken the dropouts, since each dropout will
> have a hole thru it fore and aft?
>
> Thanks. Ken
>
As several others have noted, it makes no difference strength wise if you
have the screws in or not.
The screws serve a number of purposes.
In the late 1980s Shimano set the standard for location of the rear
derailleur gear hanger bolt hole relative to the hub axle. Prior to that
there was no standard and this created some problems with index shifting.
One of the first reasons for the adjustment screws was to aid in
reinstalling rear wheels to quickly position them between the chainstays
and locate them above the derailleur for the proper chain gap.
A lot of bike frames were pretty crudely made and differences in chainstay
length of up to a 1/4" (6mm) was not uncommon. On a lot of older
derailleurs the chain gap - the distance between the jockey pulley and the
sprockets - was critical for good shifting.
Suntour and later Shimano put adjusting screws on their derailleurs ( the
"B" dimension that Peter mentioned ) for correcting this distance but
positioning the wheel forward or back was the only way to adjust the chain
gap with derailleurs based on Campy's 1960s Record design which many
makers copied.
On some older frames with short Chainstays moving the wheel back or
forward was the only way to correct for chain length problems.
One other thing, on a lot of bikes you could adjust the head tube angle by
a degree or so by moving the rear wheel position. It's questionable
whether this was a design function or just a poorly built frame.
I've seen older bike that you could change the head tube angle from 72° to
75° with the old, long Campy 1010 rear dropouts. I've heard tell that you
could use the same bike for criterium and road racing.
The right adjusting screw can help a little in preventing wheel suck -
where the wheel shifts and rubs on the left chainstay usually from honking
or sprinting.
The first generation? of Suntour dropouts with a derailleur hanger and
adjusting screws had a propensity to break off at the adjusting screw
hole. These were the dropouts that had a wider attachment point for the
seatstays. They were probably made from a hardened low strength steel.
It was the left dropout that usually broke and was probably the result of
wheel suck.
Chas.
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| | |
Date: 24 Jun 2007 18:23:55
From: A Muzi
Subject: Re: Question on rear dropout adjusting screws
|
> "kwalters" <kwalters@frii.com> wrote:
>> Have an older steel frame with adjusting screws in each dropout.
>> Just what do these do? Compensate for misaligned dropouts? Allow
>> the wheelbase to be shortened/lengthened? Both former and latter?
>> If I take them out, do I weaken the dropouts, since each dropout will
>> have a hole thru it fore and aft?
* * Chas wrote:
> As several others have noted, it makes no difference strength wise if you
> have the screws in or not.
>
> The screws serve a number of purposes.
>
> In the late 1980s Shimano set the standard for location of the rear
> derailleur gear hanger bolt hole relative to the hub axle. Prior to that
> there was no standard and this created some problems with index shifting.
>
> One of the first reasons for the adjustment screws was to aid in
> reinstalling rear wheels to quickly position them between the chainstays
> and locate them above the derailleur for the proper chain gap.
>
> A lot of bike frames were pretty crudely made and differences in chainstay
> length of up to a 1/4" (6mm) was not uncommon. On a lot of older
> derailleurs the chain gap - the distance between the jockey pulley and the
> sprockets - was critical for good shifting.
>
> Suntour and later Shimano put adjusting screws on their derailleurs ( the
> "B" dimension that Peter mentioned ) for correcting this distance but
> positioning the wheel forward or back was the only way to adjust the chain
> gap with derailleurs based on Campy's 1960s Record design which many
> makers copied.
>
> On some older frames with short Chainstays moving the wheel back or
> forward was the only way to correct for chain length problems.
>
> One other thing, on a lot of bikes you could adjust the head tube angle by
> a degree or so by moving the rear wheel position. It's questionable
> whether this was a design function or just a poorly built frame.
>
> I've seen older bike that you could change the head tube angle from 72° to
> 75° with the old, long Campy 1010 rear dropouts. I've heard tell that you
> could use the same bike for criterium and road racing.
>
> The right adjusting screw can help a little in preventing wheel suck -
> where the wheel shifts and rubs on the left chainstay usually from honking
> or sprinting.
>
> The first generation? of Suntour dropouts with a derailleur hanger and
> adjusting screws had a propensity to break off at the adjusting screw
> hole. These were the dropouts that had a wider attachment point for the
> seatstays. They were probably made from a hardened low strength steel.
>
> It was the left dropout that usually broke and was probably the result of
> wheel suck.
That's an odd assessment.
I've built with Suntour's forged ends and do quite a bit of frame
repair. IMHO the forged ends of the era (1960s~1970s) are high quality
and much more ductile, hence forgiving, than the later brittle cast SCM
ends which replaced them. Cast ends are cleaner as delivered and take
less prep time but don't move much before cracking when things go awry.
Suntour, Campagnolo and Shimano forged ends are all similar and of good
quality in my experience.
Pressed 5mm ends are another thing altogether.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | |
Date: 24 Jun 2007 18:34:49
From: * * Chas
Subject: Re: Question on rear dropout adjusting screws
|
"A Muzi" <am@yellowjersey.org > wrote in message
news:137tv947t8fi3d0@corp.supernews.com...
> > "kwalters" <kwalters@frii.com> wrote:
> >> Have an older steel frame with adjusting screws in each dropout.
> >> Just what do these do? Compensate for misaligned dropouts? Allow
> >> the wheelbase to be shortened/lengthened? Both former and latter?
> >> If I take them out, do I weaken the dropouts, since each dropout will
> >> have a hole thru it fore and aft?
>
> * * Chas wrote:
> > As several others have noted, it makes no difference strength wise if
you
> > have the screws in or not.
> >
> > The screws serve a number of purposes.
> >
> > In the late 1980s Shimano set the standard for location of the rear
> > derailleur gear hanger bolt hole relative to the hub axle. Prior to
that
> > there was no standard and this created some problems with index
shifting.
> >
> > One of the first reasons for the adjustment screws was to aid in
> > reinstalling rear wheels to quickly position them between the
chainstays
> > and locate them above the derailleur for the proper chain gap.
> >
> > A lot of bike frames were pretty crudely made and differences in
chainstay
> > length of up to a 1/4" (6mm) was not uncommon. On a lot of older
> > derailleurs the chain gap - the distance between the jockey pulley and
the
> > sprockets - was critical for good shifting.
> >
> > Suntour and later Shimano put adjusting screws on their derailleurs
( the
> > "B" dimension that Peter mentioned ) for correcting this distance but
> > positioning the wheel forward or back was the only way to adjust the
chain
> > gap with derailleurs based on Campy's 1960s Record design which many
> > makers copied.
> >
> > On some older frames with short Chainstays moving the wheel back or
> > forward was the only way to correct for chain length problems.
> >
> > One other thing, on a lot of bikes you could adjust the head tube
angle by
> > a degree or so by moving the rear wheel position. It's questionable
> > whether this was a design function or just a poorly built frame.
> >
> > I've seen older bike that you could change the head tube angle from
72° to
> > 75° with the old, long Campy 1010 rear dropouts. I've heard tell that
you
> > could use the same bike for criterium and road racing.
> >
> > The right adjusting screw can help a little in preventing wheel suck -
> > where the wheel shifts and rubs on the left chainstay usually from
honking
> > or sprinting.
> >
> > The first generation? of Suntour dropouts with a derailleur hanger and
> > adjusting screws had a propensity to break off at the adjusting screw
> > hole. These were the dropouts that had a wider attachment point for
the
> > seatstays. They were probably made from a hardened low strength steel.
> >
> > It was the left dropout that usually broke and was probably the result
of
> > wheel suck.
>
> That's an odd assessment.
> I've built with Suntour's forged ends and do quite a bit of frame
> repair. IMHO the forged ends of the era (1960s~1970s) are high quality
> and much more ductile, hence forgiving, than the later brittle cast SCM
> ends which replaced them. Cast ends are cleaner as delivered and take
> less prep time but don't move much before cracking when things go awry.
> Suntour, Campagnolo and Shimano forged ends are all similar and of good
> quality in my experience.
>
> Pressed 5mm ends are another thing altogether.
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
The Suntour dropouts from the early 1970s with the wider seat stay
attachment points were really hard on the surface. I removed the fender
eyelets off of at least one set and they were almost too hard to file. I
had to use a grinder. It's hard to say whether they were cast or forged -
I don't remember.
Most of the forged dropouts were made of much tougher steel. This is a
moot point since most bikes today come with much better designed dropouts.
Chas.
|
| | |
Date: 23 Jun 2007 15:51:45
From: jim beam
Subject: Re: Question on rear dropout adjusting screws
|
* * Chas wrote:
> "kwalters" <kwalters@frii.com> wrote in message
> news:137oufskp5vpb6d@corp.supernews.com...
>> Have an older steel frame with adjusting screws in each dropout.
>> Just what do these do? Compensate for misaligned dropouts? Allow
>> the wheelbase to be shortened/lengthened? Both former and latter?
>>
>> If I take them out, do I weaken the dropouts, since each dropout will
>> have a hole thru it fore and aft?
>>
>> Thanks. Ken
>>
>
> As several others have noted, it makes no difference strength wise if you
> have the screws in or not.
>
> The screws serve a number of purposes.
>
> In the late 1980s Shimano set the standard for location of the rear
> derailleur gear hanger bolt hole relative to the hub axle. Prior to that
> there was no standard and this created some problems with index shifting.
>
> One of the first reasons for the adjustment screws was to aid in
> reinstalling rear wheels to quickly position them between the chainstays
> and locate them above the derailleur for the proper chain gap.
>
> A lot of bike frames were pretty crudely made and differences in chainstay
> length of up to a 1/4" (6mm) was not uncommon. On a lot of older
> derailleurs the chain gap - the distance between the jockey pulley and the
> sprockets - was critical for good shifting.
>
> Suntour and later Shimano put adjusting screws on their derailleurs ( the
> "B" dimension that Peter mentioned ) for correcting this distance but
> positioning the wheel forward or back was the only way to adjust the chain
> gap with derailleurs based on Campy's 1960s Record design which many
> makers copied.
>
> On some older frames with short Chainstays moving the wheel back or
> forward was the only way to correct for chain length problems.
>
> One other thing, on a lot of bikes you could adjust the head tube angle by
> a degree or so by moving the rear wheel position. It's questionable
> whether this was a design function or just a poorly built frame.
>
> I've seen older bike that you could change the head tube angle from 72� to
> 75� with the old, long Campy 1010 rear dropouts. I've heard tell that you
> could use the same bike for criterium and road racing.
>
> The right adjusting screw can help a little in preventing wheel suck -
> where the wheel shifts and rubs on the left chainstay usually from honking
> or sprinting.
>
> The first generation? of Suntour dropouts with a derailleur hanger and
> adjusting screws had a propensity to break off at the adjusting screw
> hole. These were the dropouts that had a wider attachment point for the
> seatstays. They were probably made from a hardened low strength steel.
"hardened low strength steel"??? that's an oxymoron. more likely they
were cast or just plain low strength.
>
> It was the left dropout that usually broke and was probably the result of
> wheel suck.
>
> Chas.
>
>
>
>
>
|
| | | |
Date: 23 Jun 2007 17:24:12
From: * * Chas
Subject: Re: Question on rear dropout adjusting screws
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:DKqdnU4lmOafOeDbnZ2dnUVZ_hOdnZ2d@speakeasy.net...
> * * Chas wrote:
> > "kwalters" <kwalters@frii.com> wrote in message
> > news:137oufskp5vpb6d@corp.supernews.com...
> >> Have an older steel frame with adjusting screws in each dropout.
> >> Just what do these do? Compensate for misaligned dropouts? Allow
> >> the wheelbase to be shortened/lengthened? Both former and latter?
> >>
> >> If I take them out, do I weaken the dropouts, since each dropout will
> >> have a hole thru it fore and aft?
> >>
> >> Thanks. Ken
> >>
> >
> > As several others have noted, it makes no difference strength wise if
you
> > have the screws in or not.
> >
> > The screws serve a number of purposes.
> >
> > In the late 1980s Shimano set the standard for location of the rear
> > derailleur gear hanger bolt hole relative to the hub axle. Prior to
that
> > there was no standard and this created some problems with index
shifting.
> >
> > One of the first reasons for the adjustment screws was to aid in
> > reinstalling rear wheels to quickly position them between the
chainstays
> > and locate them above the derailleur for the proper chain gap.
> >
> > A lot of bike frames were pretty crudely made and differences in
chainstay
> > length of up to a 1/4" (6mm) was not uncommon. On a lot of older
> > derailleurs the chain gap - the distance between the jockey pulley and
the
> > sprockets - was critical for good shifting.
> >
> > Suntour and later Shimano put adjusting screws on their derailleurs
( the
> > "B" dimension that Peter mentioned ) for correcting this distance but
> > positioning the wheel forward or back was the only way to adjust the
chain
> > gap with derailleurs based on Campy's 1960s Record design which many
> > makers copied.
> >
> > On some older frames with short Chainstays moving the wheel back or
> > forward was the only way to correct for chain length problems.
> >
> > One other thing, on a lot of bikes you could adjust the head tube
angle by
> > a degree or so by moving the rear wheel position. It's questionable
> > whether this was a design function or just a poorly built frame.
> >
> > I've seen older bike that you could change the head tube angle from
72? to
> > 75? with the old, long Campy 1010 rear dropouts. I've heard tell that
you
> > could use the same bike for criterium and road racing.
> >
> > The right adjusting screw can help a little in preventing wheel suck -
> > where the wheel shifts and rubs on the left chainstay usually from
honking
> > or sprinting.
> >
> > The first generation? of Suntour dropouts with a derailleur hanger and
> > adjusting screws had a propensity to break off at the adjusting screw
> > hole. These were the dropouts that had a wider attachment point for
the
> > seatstays. They were probably made from a hardened low strength steel.
>
> "hardened low strength steel"??? that's an oxymoron. more likely they
> were cast or just plain low strength.
>
They could have been made of case hardened 1018 low carbon steel FOOL!
Chas.
|
| | | | |
Date: 23 Jun 2007 17:50:07
From: jim beam
Subject: Re: Question on rear dropout adjusting screws
|
* * Chas wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:DKqdnU4lmOafOeDbnZ2dnUVZ_hOdnZ2d@speakeasy.net...
>> * * Chas wrote:
>>> "kwalters" <kwalters@frii.com> wrote in message
>>> news:137oufskp5vpb6d@corp.supernews.com...
>>>> Have an older steel frame with adjusting screws in each dropout.
>>>> Just what do these do? Compensate for misaligned dropouts? Allow
>>>> the wheelbase to be shortened/lengthened? Both former and latter?
>>>>
>>>> If I take them out, do I weaken the dropouts, since each dropout will
>>>> have a hole thru it fore and aft?
>>>>
>>>> Thanks. Ken
>>>>
>>> As several others have noted, it makes no difference strength wise if
> you
>>> have the screws in or not.
>>>
>>> The screws serve a number of purposes.
>>>
>>> In the late 1980s Shimano set the standard for location of the rear
>>> derailleur gear hanger bolt hole relative to the hub axle. Prior to
> that
>>> there was no standard and this created some problems with index
> shifting.
>>> One of the first reasons for the adjustment screws was to aid in
>>> reinstalling rear wheels to quickly position them between the
> chainstays
>>> and locate them above the derailleur for the proper chain gap.
>>>
>>> A lot of bike frames were pretty crudely made and differences in
> chainstay
>>> length of up to a 1/4" (6mm) was not uncommon. On a lot of older
>>> derailleurs the chain gap - the distance between the jockey pulley and
> the
>>> sprockets - was critical for good shifting.
>>>
>>> Suntour and later Shimano put adjusting screws on their derailleurs
> ( the
>>> "B" dimension that Peter mentioned ) for correcting this distance but
>>> positioning the wheel forward or back was the only way to adjust the
> chain
>>> gap with derailleurs based on Campy's 1960s Record design which many
>>> makers copied.
>>>
>>> On some older frames with short Chainstays moving the wheel back or
>>> forward was the only way to correct for chain length problems.
>>>
>>> One other thing, on a lot of bikes you could adjust the head tube
> angle by
>>> a degree or so by moving the rear wheel position. It's questionable
>>> whether this was a design function or just a poorly built frame.
>>>
>>> I've seen older bike that you could change the head tube angle from
> 72? to
>>> 75? with the old, long Campy 1010 rear dropouts. I've heard tell that
> you
>>> could use the same bike for criterium and road racing.
>>>
>>> The right adjusting screw can help a little in preventing wheel suck -
>>> where the wheel shifts and rubs on the left chainstay usually from
> honking
>>> or sprinting.
>>>
>>> The first generation? of Suntour dropouts with a derailleur hanger and
>>> adjusting screws had a propensity to break off at the adjusting screw
>>> hole. These were the dropouts that had a wider attachment point for
> the
>>> seatstays. They were probably made from a hardened low strength steel.
>> "hardened low strength steel"??? that's an oxymoron. more likely they
>> were cast or just plain low strength.
>>
>
> They could have been made of case hardened 1018 low carbon steel FOOL!
>
joke presumably?
|
| | | | | |
Date: 24 Jun 2007 11:35:08
From: * * Chas
Subject: Re: Question on rear dropout adjusting screws
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:GaedncOZGa4iIuDbnZ2dnUVZ_r3inZ2d@speakeasy.net...
> * * Chas wrote:
> > "jim beam" <spamvortex@bad.example.net> wrote in message
> > news:DKqdnU4lmOafOeDbnZ2dnUVZ_hOdnZ2d@speakeasy.net...
> >> * * Chas wrote:
> >>> "kwalters" <kwalters@frii.com> wrote in message
> >>> news:137oufskp5vpb6d@corp.supernews.com...
> >>>> Have an older steel frame with adjusting screws in each dropout.
> >>>> Just what do these do? Compensate for misaligned dropouts? Allow
> >>>> the wheelbase to be shortened/lengthened? Both former and latter?
> >>>>
> >>>> If I take them out, do I weaken the dropouts, since each dropout
will
> >>>> have a hole thru it fore and aft?
> >>>>
> >>>> Thanks. Ken
> >>>>
> >>> As several others have noted, it makes no difference strength wise
if
> > you
> >>> have the screws in or not.
> >>>
> >>> The screws serve a number of purposes.
> >>>
> >>> In the late 1980s Shimano set the standard for location of the rear
> >>> derailleur gear hanger bolt hole relative to the hub axle. Prior to
> > that
> >>> there was no standard and this created some problems with index
> > shifting.
> >>> One of the first reasons for the adjustment screws was to aid in
> >>> reinstalling rear wheels to quickly position them between the
> > chainstays
> >>> and locate them above the derailleur for the proper chain gap.
> >>>
> >>> A lot of bike frames were pretty crudely made and differences in
> > chainstay
> >>> length of up to a 1/4" (6mm) was not uncommon. On a lot of older
> >>> derailleurs the chain gap - the distance between the jockey pulley
and
> > the
> >>> sprockets - was critical for good shifting.
> >>>
> >>> Suntour and later Shimano put adjusting screws on their derailleurs
> > ( the
> >>> "B" dimension that Peter mentioned ) for correcting this distance
but
> >>> positioning the wheel forward or back was the only way to adjust the
> > chain
> >>> gap with derailleurs based on Campy's 1960s Record design which many
> >>> makers copied.
> >>>
> >>> On some older frames with short Chainstays moving the wheel back or
> >>> forward was the only way to correct for chain length problems.
> >>>
> >>> One other thing, on a lot of bikes you could adjust the head tube
> > angle by
> >>> a degree or so by moving the rear wheel position. It's questionable
> >>> whether this was a design function or just a poorly built frame.
> >>>
> >>> I've seen older bike that you could change the head tube angle from
> > 72? to
> >>> 75? with the old, long Campy 1010 rear dropouts. I've heard tell
that
> > you
> >>> could use the same bike for criterium and road racing.
> >>>
> >>> The right adjusting screw can help a little in preventing wheel
suck -
> >>> where the wheel shifts and rubs on the left chainstay usually from
> > honking
> >>> or sprinting.
> >>>
> >>> The first generation? of Suntour dropouts with a derailleur hanger
and
> >>> adjusting screws had a propensity to break off at the adjusting
screw
> >>> hole. These were the dropouts that had a wider attachment point for
> > the
> >>> seatstays. They were probably made from a hardened low strength
steel.
> >> "hardened low strength steel"??? that's an oxymoron. more likely
they
> >> were cast or just plain low strength.
> >>
> >
> > They could have been made of case hardened 1018 low carbon steel FOOL!
> >
>
> joke presumably?
The lower priced Swedish made Crescents came with Suntour dropouts (DB531
tubing, Nervex lugs, racing geometry). We sold a number of these and they
were the most common bike that I saw with broken rear dropouts - usually
the left one, broken off at the adjuster screw hole.
The surface of these dropouts was hard, the serrations on the lock nuts
and QRs didn't dig in very much. This could have contributed to wheel
suck.
Campy and Simplex dropouts would bend before breaking and it was usually
the right side from the derailleur running into the wheel.
My thinking was that Suntour intentionally made these hard to prevent the
serrations from digging in. There wasn't much sport cycling in Japan at
the time. Most people rode 50 Lb. black, rusted out rod brake beasts for
basic transportation.
Keirin track racing was popular but it's a sport in the sense that
thoroughbred horse racing is a sport. The main raison d'être for Keirin
racing is parimutuel betting - gambling!
The Keirin jockeys er riders were treated more like thoroughbred horses
than athletes. You can say the same for a lot of other sports but Keirin
racing in Japan was no different than going to the track and throwing some
money at a nag.
For this reason, Japanese bikes and components in the early 1970s left a
lot to be desired. Suntour rear derailleurs and later Shimano derailleurs
had a leg up in performance over European products but the Japanese didn't
use many of their sport cycling products at home. Their bikes and
components were made for export and built to the specs of the importers in
the US and Europe.
Chas.
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Date: 23 Jun 2007 19:50:08
From:
Subject: Re: Question on rear dropout adjusting screws
|
Ken Walters writes:
> Have an older steel frame with adjusting screws in each dropout.
> Just what do these do? Compensate for misaligned dropouts? Allow
> the wheelbase to be shortened/lengthened? Both former and latter?
They stop the wheel when it is at the depth of engagement you want.
This was done so that fixed gear riders could set their chain tension
and switch back and forth between fixed gear and derailleur wheels.
Then after a while the depth of slot was made shorter and finally the
fixed gear idea went away, it being a bit of folklore.
I believe the concept arose because only track riders who rode indoor
tracks were in good condition after each winter and it was said that
the fixed gear was the key. No one noticed that these riders rode
much of the winter while many road riders sat it out. It's like the
belief in Power Cranks. They'll go away.
> If I take them out, do I weaken the dropouts, since each dropout
> will have a hole through it fore and aft?
The derailleur sifts better if the axle is not at the end of the slot
but if that isn't noticeable, take them out. Besides, their ends get
bent when they bump into a solid object. I made my own vertical
dropouts that Cinelli used when making my bicycles in the 1960's...,
before he gave a set to his friend Tullio, who put them into
production.
Jobst Brandt
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Date: 23 Jun 2007 09:20:21
From: Qui si parla Campagnolo
Subject: Re: Question on rear dropout adjusting screws
|
On Jun 23, 8:42 am, still me <wheeled...@yahoo.com > wrote:
> On Sat, 23 Jun 2007 05:41:38 -0700, Qui si parla Campagnolo
>
> <p...@vecchios.com> wrote:
> >Did adjust for less than straight frames and also acted as a b limit
> >screw, moving top pulley away from the cogs(slide wheel aft), before
> >there were b limit screws.
>
> >Removing them has no effect on dropout strength.
>
> Hmm.. maybe it's just me, but I never set the screws for "back as far
> as possible. Typically I have mine at about "1/3 from the rear".
>
> I've always treated it like a gauge or meter - normal operation should
> be somewhere near the middle third of the gauge, not at either
> extreme.
Me neither. I place them in my Merckx so that the line of the seatstay
lines up with the axle but for bigg-ish freewheels, like 13-28s,
sometimes gotta move the wheel aft to get the top pulley off the
biggest cog, and still have enough chain for big-big combo.
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Date: 23 Jun 2007 08:10:46
From: datakoll
Subject: Re: Question on rear dropout adjusting screws
|
hmmm. try roping the hub rearward with a shock cord, or find a friend
or otherwise with a hand to push the wheel against the screw set
midway then align the rim-best to align with the tire off-as evenly
spaced sighted along the rim then against the seat tube
the visible seat tube % to the right of the right rim edge should be a
rectangle not a parallelogram
the screw is loose in the hole. there is a thread percentage. a high
thread percentage means there's more metal in there than space, more
grip but removal is harder. that's what loctite does, it fills the
void between make and female threads so the screw doesn't wiggle and
slide on a ramp to go in or out.
you can blue loctite the screws in place after cleaning the surfaces
with CHO
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Date: 23 Jun 2007 05:41:38
From: Qui si parla Campagnolo
Subject: Re: Question on rear dropout adjusting screws
|
On Jun 22, 7:40 pm, kwalters <kwalt...@frii.com > wrote:
> Have an older steel frame with adjusting screws in each dropout.
> Just what do these do? Compensate for misaligned dropouts? Allow
> the wheelbase to be shortened/lengthened? Both former and latter?
>
> If I take them out, do I weaken the dropouts, since each dropout will
> have a hole thru it fore and aft?
>
> Thanks. Ken
Did adjust for less than straight frames and also acted as a b limit
screw, moving top pulley away from the cogs(slide wheel aft), before
there were b limit screws.
Removing them has no effect on dropout strength.
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Date: 23 Jun 2007 14:42:33
From: still me
Subject: Re: Question on rear dropout adjusting screws
|
On Sat, 23 Jun 2007 05:41:38 -0700, Qui si parla Campagnolo
<peter@vecchios.com > wrote:
>Did adjust for less than straight frames and also acted as a b limit
>screw, moving top pulley away from the cogs(slide wheel aft), before
>there were b limit screws.
>
>Removing them has no effect on dropout strength.
Hmm.. maybe it's just me, but I never set the screws for "back as far
as possible. Typically I have mine at about "1/3 from the rear".
I've always treated it like a gauge or meter - normal operation should
be somewhere near the middle third of the gauge, not at either
extreme.
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Date: 22 Jun 2007 23:44:14
From: David L. Johnson
Subject: Re: Question on rear dropout adjusting screws
|
kwalters wrote:
> Have an older steel frame with adjusting screws in each dropout.
> Just what do these do? Compensate for misaligned dropouts? Allow
> the wheelbase to be shortened/lengthened? Both former and latter?
Both. Dropouts often were poorly aligned, and these screws took care of
much of the problem. Also, you could decide whether to lengthen/shorten
the wheelbase a bit and still be able to quickly mount a wheel.
>
> If I take them out, do I weaken the dropouts, since each dropout will
> have a hole thru it fore and aft?
Umm, the hole is already there, whether or not there is a screw in it.
You can't weaken the dropout by removing the screw.
--
David L. Johnson
Anyone who is capable of getting themselves made President should on
no account be allowed to do the job.
-- Douglas Adams
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Date: 22 Jun 2007 22:26:21
From:
Subject: Re: Question on rear dropout adjusting screws
|
On Fri, 22 Jun 2007 23:44:14 -0400, "David L. Johnson"
<david.johnson@lehigh.edu > wrote:
>kwalters wrote:
>> Have an older steel frame with adjusting screws in each dropout.
>> Just what do these do? Compensate for misaligned dropouts? Allow
>> the wheelbase to be shortened/lengthened? Both former and latter?
>
>Both. Dropouts often were poorly aligned, and these screws took care of
>much of the problem. Also, you could decide whether to lengthen/shorten
>the wheelbase a bit and still be able to quickly mount a wheel.
>>
>> If I take them out, do I weaken the dropouts, since each dropout will
>> have a hole thru it fore and aft?
>
>Umm, the hole is already there, whether or not there is a screw in it.
>You can't weaken the dropout by removing the screw.
Dear David,
Wood isn't metal, and the dropouts probably aren't stressed enough to
matter, but Professor Gordon _may_ disagree with you:
"In general, fastenings like nails and screws do not much weaken
timber, always provided that they are in place and fit tightly. Once
they are removed, however, the resulting hole has a much more serious
effect; and no doubt the same is true of knots in timber. In a highly
stressed wooden structure, such as a glider or a yacht's mast, it is
therefore wise to leave unwanted nails and screws alone and not try to
pull them out. If needs be, they can be cut off flush with the surface
of the wood."
--"Structures," J.E. Gordon, p. 283
http://books.google.com/books?id=wQ0THyS6k4QC&pg=RA1-PA283&lpg=RA1-PA283&dq=gordon+nails+wood+mast+structures&source=web&ots=miKFY571hm&sig=GxfYm6WmVQiK76SWbuJKGIhGYBo
Possibly some engineers will discuss how much threaded bolts in metal
dropouts resemble threaded screws in wooden masts. It may turn out
that they're as different as night and day.
Cheers,
Carl Fogel
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Date: 24 Jun 2007 15:38:09
From: A Muzi
Subject: Re: Question on rear dropout adjusting screws
|
>> kwalters wrote:
>>> Have an older steel frame with adjusting screws in each dropout.
>>> Just what do these do? Compensate for misaligned dropouts? Allow
>>> the wheelbase to be shortened/lengthened? Both former and latter?
>> Both. Dropouts often were poorly aligned, and these screws took care of
>> much of the problem. Also, you could decide whether to lengthen/shorten
>> the wheelbase a bit and still be able to quickly mount a wheel.
>>> If I take them out, do I weaken the dropouts, since each dropout will
>>> have a hole thru it fore and aft?
> "David L. Johnson" <david.johnson@lehigh.edu> wrote:
>> Umm, the hole is already there, whether or not there is a screw in it.
>> You can't weaken the dropout by removing the screw.
carlfogel@comcast.net wrote:
> Wood isn't metal, and the dropouts probably aren't stressed enough to
> matter, but Professor Gordon _may_ disagree with you:
>
> "In general, fastenings like nails and screws do not much weaken
> timber, always provided that they are in place and fit tightly. Once
> they are removed, however, the resulting hole has a much more serious
> effect; and no doubt the same is true of knots in timber. In a highly
> stressed wooden structure, such as a glider or a yacht's mast, it is
> therefore wise to leave unwanted nails and screws alone and not try to
> pull them out. If needs be, they can be cut off flush with the surface
> of the wood."
> --"Structures," J.E. Gordon, p. 283
> http://books.google.com/books?id=wQ0THyS6k4QC&pg=RA1-PA283&lpg=RA1-PA283&dq=gordon+nails+wood+mast+structures&source=web&ots=miKFY571hm&sig=GxfYm6WmVQiK76SWbuJKGIhGYBo
> Possibly some engineers will discuss how much threaded bolts in metal
> dropouts resemble threaded screws in wooden masts. It may turn out
> that they're as different as night and day.
Having reworked a large number of broken bicycle frame ends, I don't
believe it matters.
(I'm blissfully ignorant of wood in its entirety).
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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| | | |
Date: 23 Jun 2007 20:00:17
From:
Subject: Re: Question on rear dropout adjusting screws
|
Carl Fogel writes:
>>> Have an older steel frame with adjusting screws in each dropout.
>>> Just what do these do? Compensate for misaligned dropouts? Allow
>>> the wheelbase to be shortened/lengthened? Both former and latter?
>> Both. Dropouts often were poorly aligned, and these screws took
>> care of much of the problem. Also, you could decide whether to
>> lengthen/shorten the wheelbase a bit and still be able to quickly
>> mount a wheel.
>>> If I take them out, do I weaken the dropouts, since each dropout
>>> will have a hole through it fore and aft?
>> Umm, the hole is already there, whether or not there is a screw in
>> it. You can't weaken the dropout by removing the screw.
> Wood isn't metal, and the dropouts probably aren't stressed enough
> to matter, but Professor Gordon _may_ disagree with you:
# In general, fastenings like nails and screws do not much weaken
# timber, always provided that they are in place and fit tightly.
# Once they are removed, however, the resulting hole has a much more
# serious effect; and no doubt the same is true of knots in timber.
# In a highly stressed wooden structure, such as a glider or a yacht's
# mast, it is therefore wise to leave unwanted nails and screws alone
# and not try to pull them out. If needs be, they can be cut off
# flush with the surface of the wood.
> --"Structures," J.E. Gordon, p. 283
http://tinyurl.com/2b7m9n
> Possibly some engineers will discuss how much threaded bolts in metal
> dropouts resemble threaded screws in wooden masts. It may turn out
> that they're as different as night and day.
They are. But the screws are loose in the holes using spring load to
keep them from changing position (as tension in spokes does for spoke
nipples.) They cannot add to rigidity, and if tight, could only
effect strength negatively an immeasurable amount, lying in the
neutral bending axis.
Jobst Brandt
|
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Date: 23 Jun 2007 13:28:42
From: jim beam
Subject: Re: Question on rear dropout adjusting screws
|
jobst.brandt@stanfordalumni.org wrote:
> Carl Fogel writes:
>
>>>> Have an older steel frame with adjusting screws in each dropout.
>>>> Just what do these do? Compensate for misaligned dropouts? Allow
>>>> the wheelbase to be shortened/lengthened? Both former and latter?
>
>>> Both. Dropouts often were poorly aligned, and these screws took
>>> care of much of the problem. Also, you could decide whether to
>>> lengthen/shorten the wheelbase a bit and still be able to quickly
>>> mount a wheel.
>
>>>> If I take them out, do I weaken the dropouts, since each dropout
>>>> will have a hole through it fore and aft?
>
>>> Umm, the hole is already there, whether or not there is a screw in
>>> it. You can't weaken the dropout by removing the screw.
>
>> Wood isn't metal, and the dropouts probably aren't stressed enough
>> to matter, but Professor Gordon _may_ disagree with you:
>
> # In general, fastenings like nails and screws do not much weaken
> # timber, always provided that they are in place and fit tightly.
> # Once they are removed, however, the resulting hole has a much more
> # serious effect; and no doubt the same is true of knots in timber.
> # In a highly stressed wooden structure, such as a glider or a yacht's
> # mast, it is therefore wise to leave unwanted nails and screws alone
> # and not try to pull them out. If needs be, they can be cut off
> # flush with the surface of the wood.
>
>> --"Structures," J.E. Gordon, p. 283
>
> http://tinyurl.com/2b7m9n
>
>> Possibly some engineers will discuss how much threaded bolts in metal
>> dropouts resemble threaded screws in wooden masts. It may turn out
>> that they're as different as night and day.
>
> They are. But the screws are loose in the holes using spring load to
> keep them from changing position (as tension in spokes does for spoke
> nipples.) They cannot add to rigidity, and if tight, could only
> effect strength negatively an immeasurable amount, lying in the
> neutral bending axis.
>
the screw holes are not in the neutral bending axis for dropout opening
- derailleur caught in spokes for example. nor in the neutral axis for
dropout torsion. they're only neutral for a strict bend about the screw
hole axis - a most unlikely scenario.
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Date: 23 Jun 2007 02:09:41
From: datakoll
Subject: Re: Question on rear dropout adjusting screws
|
rear wheel alignment is sighted to the seatpost-bike upside down,
seat off-then when the axle nuts are tightened, until you develop
technique, the wheel moves toward the side getting snugged and out of
alignment. turn with two hands at once to develop technique. hold the
wheel steady with the third hand.
the screws aid the alignment process by setting the wheel closer to
the desired alignment if not directly on the alignment as the
alignment in reality is dependent on other variables eg dish
there is an aftermarket dropout half round spacer in two parts with a
groove that sets over the dropout, with a holding screw thru the
center-does similar
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Date: 24 Jun 2007 15:14:05
From: A Muzi
Subject: Re: Question on rear dropout adjusting screws
|
datakoll wrote:
> rear wheel alignment is sighted to the seatpost-bike upside down,
> seat off-then when the axle nuts are tightened, until you develop
> technique, the wheel moves toward the side getting snugged and out of
> alignment. turn with two hands at once to develop technique. hold the
> wheel steady with the third hand.
> the screws aid the alignment process by setting the wheel closer to
> the desired alignment if not directly on the alignment as the
> alignment in reality is dependent on other variables eg dish
> there is an aftermarket dropout half round spacer in two parts with a
> groove that sets over the dropout, with a holding screw thru the
> center-does similar
Jobst does this 'upside down' (bike upright) and both of us can manage
it without frame screws. Face it, they are vestigial if you are not
racing in a supported event.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 22 Jun 2007 18:54:04
From: Jay Beattie
Subject: Re: Question on rear dropout adjusting screws
|
On Jun 22, 6:40 pm, kwalters <kwalt...@frii.com > wrote:
> Have an older steel frame with adjusting screws in each dropout.
> Just what do these do? Compensate for misaligned dropouts? Allow
> the wheelbase to be shortened/lengthened? Both former and latter?
Both. If they are something other than the long Campy 1010 drop outs,
you don't get much wheelbase adjustment.
>
> If I take them out, do I weaken the dropouts, since each dropout will
> have a hole thru it fore and aft?
No. They are frequently removed or lost. -- Jay Beattie.
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