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Frame (re)alignment

Old 04-16-21, 04:31 PM
  #1  
Shinkers
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Frame (re)alignment

Hello (lot's of questions for this forum lately...),

I have a Soma Wolverine frame that I've picked up that has some alignment issues. This frame has sliding dropouts and I can center the wheel at the chainstays without a problem. However, the wheel is around 2-3mm closer to the drive side seatstay than to the non-drive side. This would make me think that one dropout is lower than the other, but the thru-axle threads in fine so they can't be too misaligned.

When I did a string check, (running from dropout, around head tube and to other dropout) it would appear that the frame itself is actually straight since the seat tube measures center within the pulled string. This makes me think that the seat stay may just be welded slightly out of alignment. Hard to tell.

So I'm trying to decide what the best course of action is. I'm thinking that I could tweak the rear triangle over enough to correct the difference since I can center the wheel in the chainstays. This would mean that I'd actually be offsetting the rear wheel though if my string check is correct. Is there any other way to correct this? I can't see how you'd be able to actually move the dropouts vertically.

Or I can buy some fenders...
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Old 04-16-21, 04:38 PM
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Sure sounds like at face value one stay is longer then the other. The string test being is a poor one to show this. The good wheel in the frame does a better job. I would not be concerned about the couple of mms offness since the easy option is to misalign the other two factors. I think you'll find the rear wheel will end up imparting a steering force if the rear end is set off center and the wheel shifted in the drop outs to "look" straight at the chain stays.
A builder's solution (and one that isn't to be talked about...) is to saw through the short stay and install a sleeve/plug that allows that stay to grow the mm or so needed in length. Not what I suggest but doable. Andy
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Old 04-16-21, 04:39 PM
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How do you know that the rear rims dish is off?
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Old 04-16-21, 04:49 PM
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Andy,

Like one seat stay is longer than the other? This could certainly be the case since the drive side seat stay is cut to allow a belt. With the wheel centered at the chain stays everything seems to ride fine...

I do know that the wheel is straight (verified in other frames).
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Old 04-16-21, 05:32 PM
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Originally Posted by Shinkers View Post
Andy,

Like one seat stay is longer than the other? This could certainly be the case since the drive side seat stay is cut to allow a belt. With the wheel centered at the chain stays everything seems to ride fine...

I do know that the wheel is straight (verified in other frames).
So what's the problem if everything is fine? I wouldn't worry about 2 -3 mm if every thing is fine. No one will be able to tell unless you point it out to them.
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Old 04-16-21, 07:25 PM
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Originally Posted by Iride01 View Post
So what's the problem if everything is fine? I wouldn't worry about 2 -3 mm if every thing is fine. No one will be able to tell unless you point it out to them.
+1 Never Fix A Running Piece
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Old 04-16-21, 08:51 PM
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A stay splitter, if installed properly, should not effect the stay lengths. Of course if that splitter for some reason can't be fully tightened or closed... Andy (who routinely sees posts with incomplete info to only be told more in later posts)
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Old 04-17-21, 03:40 AM
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Originally Posted by Moisture View Post
How do you know that the rear rims dish is off?
Roughly, if the rim is not centered on the frame when standing behind the bike. If you want to know exactly, it needs to be checked by a dishing gauge.
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Old 04-17-21, 10:17 AM
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A simple home made dishing tool is three stacks of coins placed on a counter top that are tall enough to sit the rim/wheel on and have the down side axle above the counter top. Slide under that axle sides lock nut another stack of coins which will just clear that side's lock nut. now flip the wheel over and see how that 4th stack relates the the second side's lock nut. Costs less then $10 (dependent of what coins are used) and guess what? You get a full refund when done Andy
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