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Old 07-22-10, 12:11 PM   #1
TimeTravel_0
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cold setting steel & brake bridge

I have an old Trek touring frame that I would like to get back on the road with a selection of modern components. Since I am already going to powdercoat the frame since the original paint is in poor condition, I am considering having a local framebuilder that I know add downtube shifter braze-ons so I can use downtube shifters -- the frame came with only a clamp on. I'd also like the rear spacing to be set from 126mm to 130 or 135mm to accommodate a modern hub/drivetrain. While I am having frame work done, would it be smart to have the rear brake bridge removed and have a longer one installed to be on the safe side? Or is it fine to simply coldset as is?

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Old 07-22-10, 12:24 PM   #2
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Coldset it as is....the bridge will be OK. 130 is the back will OK.
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Old 07-22-10, 02:14 PM   #3
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if you're going from 126 to 130, I wouldn't even bother to cold-set, I've done the exact same thing (actually, a trek touring bike as well). All I do is stretch out the frame those 4mm when I place in the wheel. It's not hard at all, and I've never had a bit of trouble with it.

Is there something wrong with clamp on downtube shifters? It seems like a lot of work for very little reward getting the braze-ons.
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Old 07-22-10, 02:19 PM   #4
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yes you could simply spring the frame open every time you mount the rear wheel, but why bother. Spread the frame, and re-square the dropouts and don't worry about the brake bridge. It's a very small change in angle and will spread from the bridge down perfectly well.
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Old 07-22-10, 02:20 PM   #5
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Originally Posted by fuzz2050 View Post
if you're going from 126 to 130, I wouldn't even bother to cold-set, I've done the exact same thing (actually, a trek touring bike as well). All I do is stretch out the frame those 4mm when I place in the wheel. It's not hard at all, and I've never had a bit of trouble with it.
I've had the same experience with my Schwinn Voyageur. It takes a little effort to get the hub in there, but not much.

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Is there something wrong with clamp on downtube shifters? It seems like a lot of work for very little reward getting the braze-ons.
I agree. How much is that going to cost?
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Old 07-22-10, 02:23 PM   #6
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yes you could simply spring the frame open every time you mount the rear wheel, but why bother. Spread the frame, and re-square the dropouts and don't worry about the brake bridge. It's a very small change in angle and will spread from the bridge down perfectly well.
How do you "re-square" the dropouts? Is this really necessary for a 2mm per side change?
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Old 07-22-10, 02:30 PM   #7
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How do you "re-square" the dropouts? Is this really necessary for a 2mm per side change?
There are tools made specifically for the job, similar to this set and any decent shop would have a pair. It probably isn't enough angle change to worry about if you know the dropouts were right beforehand, but I'm of the old measure twice cut once school, and as long as I were doing the work, I'd check them before painting.
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Old 07-22-10, 03:03 PM   #8
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You can protect the Brazing joint of the brake bridge by making a jig to restrict it from spreading there,

so as to keep the bending below that point. I've seen the brazing pop off on one side in some situations, ..
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Old 07-22-10, 04:38 PM   #9
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The bad thing about putting a wider spaced rear hub into a frame is the bending load put on the axle. It can wear out the hub bearings over time.
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Old 07-22-10, 05:02 PM   #10
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I agree. How much is that going to cost?
$25

clamp-on shifters suck, that's why.

thanks everyone -- I'll go ahead and coldset away. just so this is clear, it is safe to go from 126mm to 135mm? I'd rather use a 135mm hub.
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