Bicycle Mechanics - re-dish or re-space

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Standard Issue
02-21-12, 11:14 AM
I'm doing a 7 to 10 speed drivetrain conversion on and old steel bike and I've run into a little issue with my wheelset. I'm using a DA/mavic 130mm rear wheel which I bought with no axle. I've been able to source all the parts and get it all assembled but I ran into an alignment issue. The rim is slightly off-center (to the left) of where it's supposed to be. My first instinct was to have the wheel re-dished but my second instinct is to rearrange the axle and spacers to have it propperly aligned.
Pros for rearranging axle are:
Eliminate possibility of spokes being too long/short to redish, won't weaken wheel like re-dishing might, and it costs less (I can reconfigure the axle myself)
The primary con is my concern for frame clearance as there will be less space between the cassette and stays. It's a 126mm frame and has no trouble spreading to 130.
There's plenty of clearance now but in addition to removing the tiny spacer I may also have to use a narrower locknut (the one on there is a pretty beefy mushroom nut)
I'm sure the most common answer will be "Try it and see" but I'm hoping someone will be able to answer from experience.
Egerly awaiting responses,
Alex
cny-bikeman
02-21-12, 11:30 AM
If you can respace that is better, and as long as you have sufficient clearance for the chain to run freely there's no issue with that aspect. However, respacing will also affect your chainline, which you should check either with the wheel in the dropouts or you can reset the rear triangle to 130, making sure it's centered properly.
See this page on Sheldon's site regarding both spacing and rear triangle.
http://sheldonbrown.com/frame-spacing.html
But note that the picture of the string method is inaccurate - the string should be run from the same spot on both dropouts, not tied to the upper part of one.
mrrabbit
02-21-12, 12:10 PM
1. Pop hub in as-is, see if rear dropout design allows for small cog clearance (chainstay, seatstay and dropout facing) and chain clearance (seatstay).
2. Then re-dish...
Just because you can spread a frame doesn't mean 130mm 8/9/10 speed will work - you need to test as indicated in #1.
=8-)
Standard Issue
02-21-12, 01:26 PM
1. Pop hub in as-is, see if rear dropout design allows for small cog clearance (chainstay, seatstay and dropout facing) and chain clearance (seatstay).
2. Then re-dish...
Just because you can spread a frame doesn't mean 130mm 8/9/10 speed will work - you need to test as indicated in #1.
=8-)
There's plenty of clearance between the smallest cog/lockring and frame but in order to move the whole hub/cassette to the right to center the rim, I plan on removing a spacer and using a smaller locknut which may then cause clearance issues. I guess I'm wondering how much clearance is needed. if it runs smooth on the stand, should I be ok?
Bill Kapaun
02-21-12, 02:37 PM
You really have to fit the wheel and see how much clearance you have.
Bikes just vary too much in the manner that the chain stays "angle" from the drop outs.
I did something similar a few months ago. The chain went on to the top cog fine. It wouldn't come back off it though until I spaced the wheel back over a bit.
Charles Ramsey
02-21-12, 06:38 PM
Go ahead and use spacers then one day when you are bored tighten all the spokes on the non freewheel side 1/4 turn true the wheel and redo the spacers. This is how I learned to build wheels. Doing it slowly reduces frustration expect to strip a couple of nipples. http://zerodish.wordpress.com/
mrrabbit
02-21-12, 07:13 PM
Go ahead and use spacers then one day when you are bored tighten all the spokes on the non freewheel side 1/4 turn true the wheel and redo the spacers. This is how I learned to build wheels. Doing it slowly reduces frustration expect to strip a couple of nipples. http://zerodish.wordpress.com/
Do you understand what "dish" is - in particular the two part definition to dish?
=8-)
BobLoblaw
02-22-12, 05:39 AM
It seems reasonable to assume that before the axle was removed, the wheel was dished correctly. I would re-space and reinstall the axle. If you don't, the chainline to the inboard half of the cassette will be monkeyed up, the rear D will have to reach farther inboard than it was designed to, and you will likely have rear D shifting issues.
BL
Charles Ramsey
02-22-12, 07:08 AM
Whoops my mistake. My point was if using the spacers work do that first. If there is room between the small cassette and dropout then you can use a smaller spacer there and redish your wheel making it stronger. You only need 2mm between the small cassette and dropout mine is so close that I have to use a steel lockring the aluminum duraace one is too fat. Most wheels are overdished even 10 cog ones. The biggest disadvantage to moving the cogs closer to the dropouts is it makes it harder to shift onto the smallest cog. You can remedy this by using a 1 or 2 mm spacer on the derailer fixing bolt moving the derailer out it is 10mm in diameter the spacer you took off the axel will work.
I strongly suspect that you'll find that re-dishing will end up being necessary no matter what you do, so you might as well bite the bullet and do it right.
10s on a 130mm axle is tight enough as it is, so you'll already have the flanges as far to the right as possible. The only way to move it more to the right would be to go to 135mm, which would buy you another 2.5mm when the 5mm additional spacers are added to the left. If that's enough, it's a possibility, otherwise go ahead and do the job right.
Hint---- when dishing a rim farther to the right, over loosen the left then tighten the right spokes moving the rim father than needed, and finish bringing the rim home and the tension to tatget by tightening the left spokes. That will have you working the right spokes at slightly lower tension reducing the chances of rounding off nipples. Also use a 4 corner spoke wrench for the job.
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