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Main
Date: 18 May 2007 08:35:58
From: jbollyn@gmail.com
Subject: New wider rim - now the crank arm hits the rim brake - suggestions please?
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I have replaced my bad (split) rim with a complete new rear wheel. My
LBS spec-ed and built the wheel. I installed a new tire and mounted
the wheel. The new rim is a little wider than the old rim, so I needed
to loosen the brake cable a bit. I am sad to say the left crank arm
now hits the brake. The right crank arm is OK. Here are 5 pics,
slightly different camera angles:
http://orion.neiu.edu/~jbollyn/bike/brake1a.jpg
http://orion.neiu.edu/~jbollyn/bike/brake2a.jpg
http://orion.neiu.edu/~jbollyn/bike/brake3a.jpg
http://orion.neiu.edu/~jbollyn/bike/brake4a.jpg
http://orion.neiu.edu/~jbollyn/bike/brake5a.jpg
What is the best way to fix this? Do I need to replace the crankset?
Or a different BB? Or is it possible to replace just the left crank
arm?
The brakes are relatively new, so I would rather not replace them. I
obviously want to keep the new wheel.
I have disabled the rear brake temporarily, so at least the crank will
turn without hitting the brake.
Completely confused as usual, J.
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Date: 18 May 2007 12:36:34
From: jbollyn@gmail.com
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions please?
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On May 18, 10:59 am, M-gineering <ikmotgeens...@m-gineering.nl > wrote:
> jbol...@gmail.com wrote:
> > I have replaced my bad (split) rim with a complete new rear wheel. My
> > LBS spec-ed and built the wheel. I installed a new tire and mounted
> > the wheel. The new rim is a little wider than the old rim, so I needed
> > to loosen the brake cable a bit. I am sad to say the left crank arm
> > now hits the brake. The right crank arm is OK. Here are 5 pics,
> > slightly different camera angles:
>
> > Completely confused as usual, J.
>
> V-brakes have a thick and a thin washer to mount the brakeblock to
> adjust the width of the brake. Make sure the thin one is between the
> block and the brakearm. Do not change the order of the washers though,
> you want:
> brakeblock
> narrow hollow washer
> spherical washer
> brake
> spherical washer
> tall hollow washer
> standard frlat washer
> nut
>
> Or fit narrower pads
> --
> /Marten
>
> info(apestaartje)m-gineering(punt)nl
>
Yes, I'm sure you, and the others, are right about the washers. When I
installed these brakes some months ago, I used all the washers. Just
by dumb luck, it worked out OK.
In the following instructions doc, step 2B, I think I need either the
3mm or the 6mm setting. I am just not clear on the concept yet.
Also, in step 1, I used the center brake boss hole. Will I probably
need to use one of the other holes instead?
http://www.sram.com/_media/techdocs/single-digit-ult-install.pdf
thanks - J.
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Date: 18 May 2007 11:39:23
From: Hank Wirtz
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions please?
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On May 18, 11:24 am, Alex <a...@columbia.edu > wrote:
> Most direct pull brakes use shoes mounted on studs. My guess is that
> your brake shoe on one, or both, sides is mounted near the stud end.
> Loosen the nut holding the stud and slide the shoe over so that when
> the brake is re-connected the arm does not
> stick out as much. I'm surprised your LBS did not do this for you.
> --------------------
> Alex
I've never seen a direct-pull brake with threadless studs like you
describe - only cantilever brakes and Mafac centerpulls use those. And
most cantilevers are switching to the threaded-post style pads like V-
brakes use. Like most posters have said, the OP needs to rearrange his
stack of beveled washers.
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Date: 18 May 2007 21:23:47
From: Jay
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions please?
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"Hank Wirtz" <hank@wirtznet.net > wrote in message
news:1179513563.468879.112860@l77g2000hsb.googlegroups.com...
> On May 18, 11:24 am, Alex <a...@columbia.edu> wrote:
>> Most direct pull brakes use shoes mounted on studs. My guess is that
>> your brake shoe on one, or both, sides is mounted near the stud end.
>> Loosen the nut holding the stud and slide the shoe over so that when
>> the brake is re-connected the arm does not
>> stick out as much. I'm surprised your LBS did not do this for you.
>> --------------------
>> Alex
>
> I've never seen a direct-pull brake with threadless studs like you
> describe - only cantilever brakes and Mafac centerpulls use those. And
> most cantilevers are switching to the threaded-post style pads like V-
> brakes use. Like most posters have said, the OP needs to rearrange his
> stack of beveled washers.
>
Just to clarify, my LBS spec-ed and built the wheel. They then shipped (10
miles) the wheel to me. I installed the new tube and tire, and mounted the
wheel on the bike. I then realized that I needed to adjust the washers - J.
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Date: 18 May 2007 11:24:47
From: Alex
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions please?
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Most direct pull brakes use shoes mounted on studs. My guess is that
your brake shoe on one, or both, sides is mounted near the stud end.
Loosen the nut holding the stud and slide the shoe over so that when
the brake is re-connected the arm does not
stick out as much. I'm surprised your LBS did not do this for you.
--------------------
Alex
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Date: 19 May 2007 03:06:50
From: daveornee
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions please?
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jbollyn@gmail.com Wrote:
> I have replaced my bad (split) rim with a complete new rear wheel. My
> LBS spec-ed and built the wheel. I installed a new tire and mounted
> the wheel. The new rim is a little wider than the old rim, so I needed
> to loosen the brake cable a bit. I am sad to say the left crank arm
> now hits the brake. The right crank arm is OK. Here are 5 pics,
> slightly different camera angles:
>
> http://orion.neiu.edu/~jbollyn/bike/brake1a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake2a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake3a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake4a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake5a.jpg
>
> What is the best way to fix this? Do I need to replace the crankset?
> Or a different BB? Or is it possible to replace just the left crank
> arm?
>
> The brakes are relatively new, so I would rather not replace them. I
> obviously want to keep the new wheel.
>
> I have disabled the rear brake temporarily, so at least the crank will
> turn without hitting the brake.
>
> Completely confused as usual, J.
Is the rim centered between the drop outs?
Re-do the spacers on the brakes.... as one "free" solution
--
daveornee
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Date: 18 May 2007 17:59:53
From: M-gineering
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions
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jbollyn@gmail.com wrote:
> I have replaced my bad (split) rim with a complete new rear wheel. My
> LBS spec-ed and built the wheel. I installed a new tire and mounted
> the wheel. The new rim is a little wider than the old rim, so I needed
> to loosen the brake cable a bit. I am sad to say the left crank arm
> now hits the brake. The right crank arm is OK. Here are 5 pics,
> slightly different camera angles:
>
> Completely confused as usual, J.
>
V-brakes have a thick and a thin washer to mount the brakeblock to
adjust the width of the brake. Make sure the thin one is between the
block and the brakearm. Do not change the order of the washers though,
you want:
brakeblock
narrow hollow washer
spherical washer
brake
spherical washer
tall hollow washer
standard frlat washer
nut
Or fit narrower pads
--
/Marten
info(apestaartje)m-gineering(punt)nl
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Date: 18 May 2007 18:01:18
From: Lou Holtman
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions
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jbollyn@gmail.com wrote:
> I have replaced my bad (split) rim with a complete new rear wheel. My
> LBS spec-ed and built the wheel. I installed a new tire and mounted
> the wheel. The new rim is a little wider than the old rim, so I needed
> to loosen the brake cable a bit. I am sad to say the left crank arm
> now hits the brake. The right crank arm is OK. Here are 5 pics,
> slightly different camera angles:
>
> http://orion.neiu.edu/~jbollyn/bike/brake1a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake2a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake3a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake4a.jpg
>
> http://orion.neiu.edu/~jbollyn/bike/brake5a.jpg
>
> What is the best way to fix this? Do I need to replace the crankset?
> Or a different BB? Or is it possible to replace just the left crank
> arm?
>
> The brakes are relatively new, so I would rather not replace them. I
> obviously want to keep the new wheel.
>
> I have disabled the rear brake temporarily, so at least the crank will
> turn without hitting the brake.
>
> Completely confused as usual, J.
>
Discbrakes. ;-)
Those brakes look very spread. That can't be right. Is that rim that
wide, that the pads rub against the rim? Which brakepads do you use? Can
you give us an overall picture?
Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)
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Date: 18 May 2007 11:53:45
From: David L. Johnson
Subject: Re: New wider rim - now the crank arm hits the rim brake - suggestions
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jbollyn@gmail.com wrote:
> What is the best way to fix this? Do I need to replace the crankset?
> Or a different BB? Or is it possible to replace just the left crank
> arm?
I don't think you want to do any of those things. Unfortunately your
pictures do not show the brake blocks at all. Some v-brakes have blocks
mounted on studs, allowing some in-out adjustment. If they are attached
with bolts, you can at least move washers from the inside to the outside
of the arm, moving the brake blocks outward to give you enough clearance
without opening the arms that wide.
>
> The brakes are relatively new, so I would rather not replace them. I
> obviously want to keep the new wheel.
Replacing the brake would be the next option, if you can't adjust the
blocks enough.
--
David L. Johnson
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