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Old 09-19-11, 07:03 PM   #1
Schwinnsta
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Handlebar rotating (vertically) in stem.

My handlebars on my Raleigh Sports started to rotate while I was out riding. When I got home I tightened the stem clamp but they still rotated so under pressure so I tightened some more and stripped the stem bolt. For the time being, I added three washers above the nut so that nut would be on thread. It still rotates under normal force of riding. I have a feeling the problem is with the handlebar serrations or lack their of, but the handlebars are otherwise in great shape, with good chrome. I am purchasing another Raleigh bolt (with the stem, from eBay). I would rather not have to purchase another handlebar too.

Any ideas?
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Old 09-19-11, 07:16 PM   #2
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Buy new parts, you said ...
Quote:
"so I tightened some more and stripped the stem bolt"
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Old 09-19-11, 07:37 PM   #3
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Buy new parts, you said ...
I can only get them used and it seems unlikely that the bolt was weak. My plan is that when the new, to me, bolt arrives is clean stem inside and roughen with sandpaper in horizontal direction and do the same to the handlebar clamp area, tighten and hope. These bolts are Whitworth. If this does not work I will go with the closest undersize grade 5 bolt and failing that grade 8. Since this is a vintage bike I hesitate to use English or Metric bolts but see no other choice.

Last edited by Schwinnsta; 09-19-11 at 07:38 PM. Reason: spelling
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Old 09-19-11, 07:52 PM   #4
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take a small piece of sandpaper, fold it over so the rough stuff is on both sides and slide it between the handlebar and the stem. I had a handlebar that would rotate and after doing that it hasn't moved in months.
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Old 09-19-11, 08:19 PM   #5
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Schwinnista: Make sure that there is a gap between the ears of the stem so that the bolt is tightening the clamp against the bar and not just squeezing the ears together. You may need to shim the bar to be able to clamp it sufficiently.
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Old 09-20-11, 07:06 AM   #6
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take a small piece of sandpaper, fold it over so the rough stuff is on both sides and slide it between the handlebar and the stem. I had a handlebar that would rotate and after doing that it hasn't moved in months.
Are you saying to leave the sandpaper in like a shim?
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Old 09-20-11, 07:06 AM   #7
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Schwinnista: Make sure that there is a gap between the ears of the stem so that the bolt is tightening the clamp against the bar and not just squeezing the ears together. You may need to shim the bar to be able to clamp it sufficiently.
There is a gap.
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Old 09-21-11, 07:53 PM   #8
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I thought I would bring my handlebar rotation problem to a conclusion. The new stem came. The old stem clamp had smooth shoulders at the clamp ends that sat proud of the inner part which was indented and not machined. The new clamp is serrated and the same diameter all the way through. I did strip the top of the old clamp at least as well as the thread. I had to use a vice grip to prevent it from spinning. Where the handlebar attaches to the clamp, the handlebar is smooth just chrome. I roughed both pieces a little bit and cleaned the mating surfaces with acetone so there would be no oil or wax.

The design of the old clamp with its smooth shoulders maybe 3/16" at each end for the mating surfaces is clearly problematic. Yet both clamps are marked with the Raleigh figure and are the same size.
Hopefully this the end of the problem.

Last edited by Schwinnsta; 09-21-11 at 08:00 PM. Reason: grammer
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