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Old 11-13-04, 07:39 AM   #1
handsomepete
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Rear wheel alignment on my softride

Ok, I bought this frame used and I know it was a risk, but it is in quite good shape and the price was great.

With that out of the way, when I put the rear wheel on, the tire/rim did not seem to be in perfect alignment. That is, looking at the front of the wheel inside the chainstays, it is closer to one side than the other by a small amount. The center of the tread of the tire is just a millimeter or two off center from the break caliper hole. There is no play in the wheel. However, if I turn the wheel around backward, it seems to line up perfectly. I have tried this with another rear wheel I have and it is closer to center, but still off to the left a little.

Here are the facts about the frame and wheel: 1999 powerwing 700 frame bought used. Has original paint and just a few scratches. No chips or cracked paint or anything to indicate that the races or chainstays were bent anywhere and no signs of a crash. The wheel is a Campy Shamal w/9 spd cass. and it has been installed on another frame with no problems for some time.

I have put the wheel on without the skewers and inspected the axles and they are resting fully up into the races and the races are not deformed as far as I can tell. The wheel cants to the left if you are facing the same direction as the bike. I do not have the chain, crank or derailers attached at this point.

I have stared at this bike with one eye closed from all angles until I have a headache. To be honest, the wheel looks straight if you eyeball it from the rear. It's almost as if it is dished to the side a little. Is there any way to test the alignment of the frame? I thought I might complete the bike and paint the tire tread or something like that and see if the tread wear indicates anything funky.

I am quite experienced in building bikes and have done my share of engineering to make them right. I would like to try to fix this at home if possible, since the whole point of buying the used frame was to save money. Any adjustment would be horizontal, ie. shifting one race back or forward very slightly to bring the wheel into alignment. However, this would result in a hole slightly larger than is required to fit the axel into, and the skewers would have to be strong and tight to hold the wheel in place. However, I think that's how most dropouts are anyway to some extent. There would be no need for an expansion of either hole up or down, as this part is in alignment.

The alternative would be determining which chainstay would need to be slightly bent to correct the problem. However, this seems to be more drastic to me than grinding a little out of the hole.

If anyone has any experience or thoughts on this manner, they would be appreciated.

thanks
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Old 11-13-04, 08:12 AM   #2
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You could use a ***, i.e., a frame alignment guage from Park Tools. Another quick, easy and cheap thing I've done is tie a thread in one dropout, pull it to around the headtube, then pull it around to the other dropout, then tie it. Now, measure the distance between the thread and the seat tube on both sides and compare.

If you are using a wheel to check straightness of the rear end of the bike, you have to make sure that the wheel is absolutely true and dished properly! Also, tires don't always seat exactly right, so be aware.
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Old 11-13-04, 10:31 AM   #3
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It sounds to me like your problem is much more likely to be your wheel than your bike. In this case, that's a good thing.

Take your wheel to an average or better LBS. Ask them to check and, if necessary, redish your rear wheel. Once you're sure that your wheel is right you can judge better if you need to mess with your frame. My bet is that the wheel work alone will solve your problem.
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Old 11-13-04, 11:48 AM   #4
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Good advice from both Drevil and Retrogtouch. Get the dishing and true verified. Then check on the frame without the tire mounted, to minimize any impact.

If it's still out, you can perform Drevil's string check. The brake and front derailleur post should be just high enough, even though the Powerwing does not have a seat tube. However, if things indicate an alignment problem, you still need to determine if the wheel is skewed relative to the longitudinal axis of the frame, or simply offest, but parallel ot this axis.

To check tracking, tie a string around the rear rim in the 8:00 o'clock position (when viewed from drive side). Stand in front of the bicycle and pull the string taught and move it laterally until it just grazes the rear rim at the 4:00 o'clock position. A perfect tracking bicycle will have the string just graze the front wheel at the 4:00 and 8:00 o'clock positions. If it doesn't, turn the steering so that the front rim grazes the string at the 8:00 o'clock position and measure the distance between the string and front rim at the 4:00 o'clock position. This measurement will be 2x the apparent misalignment at the rear stays if it is simply offset, but 9.3x if the wheel if skewed (assuming 700C rims, typical 1000mm wheelbase). You'll find a extra person or two is handy when performing this check.

The fact that the Powerwing is made for from heat treated aluminum and has such large chainstay sections makes it impractical to cold set a misaligned frame. Filing the vertical dropouts will only correct for a skewed rear wheel. Small parallel offset is easily remedied by removing or adding washers/spacers on the rear hub.

Good luck with the Powerwing. Some people find it impossible to adjust to the beam. Personally, my quads were too big and rubbed on the beam due to its width and high position. It was OK in cycling shorts, but when riding in a bathing suit during a triathlon, the chaffing was terrible. Even liberal applications of Vaseline did not help. Within a year I sold mine a got a GT Vengeance. I went from the most comfortable to the harshest ride possible.
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Old 11-13-04, 01:46 PM   #5
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In addition to what these guys have said, using the Park "Frame and Fork Dropout Alignment Guages" would probably be useful. I'd imagine that your LBS would have a set of these and it should be a relatively "simple" matter.

http://www.parktool.com/repair_help/FFG.shtml

I do, however, feel like it's the wheel that's causing the problem. A simple dishing guage would determine that in a quick matter.
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Old 11-13-04, 04:03 PM   #6
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Many thanks to you all for the great info. I now have quite a few tests I can run to see what's up. I will reply back and let ya'll know what I find.

thanks again.
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Old 11-13-04, 10:49 PM   #7
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I have a Softride. There is a bolt at the front of the beam that holds it to the frame. Softride recomends that it is changed every three years. Maybe you should change it out. Mine never broke but I saw one break on a tandem. The person feel off the bike when it broke. I have broken the other bolt. The one for the adjustment for raising/ lowering the beam. You don't have to tighten this one much at all.
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Old 11-17-04, 07:20 PM   #8
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Thanks Jayhop, I will. I was wondering about that bolt. Hey, I was born in Witchita
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