skelly

Any tips on centering a chainring on the spider? I'm having some loose/tight tension and I know the ring must not be centered. I already know to tighten all the bolts evenly but I'm still having problems. Just wondering if there's any other tips any of you might offer to help me get this thing centered properly.

I wouldn't be as concerned if it was only a small difference but at it's tightest it feels like it's about to snap off, and at it's loosest it would easily fall off.. big difference.

Thanks in advance.

FixedDrinks

Try this. Just did it to mine; works pretty well:
https://sheldonbrown.com/fixed.html#tension

manboy

I've heard you want to tighten the bolts a little and then gently rotate it a few times to even the tension and center it, and then tighten all the bolts evenly. Also, as on car wheels, I think you want to tighten in a star pattern.

drolldurham

sheldon brown has a guide for centering a chainring on his website.... brb with the link

edit: nevermind. see above

skelly

Yeah I saw that aritcle and the previous thread on this issue. I've tried all that. I always tighten each one gently going around the ring like 8 times and never 2 in a row.

I've removed and retightened this chainring like 25 times today. It looks perfectly centered on the spider. I can't figure this out. It's a BIG difference. Like when it's loose I could easily remove the chain. When it's tight I can only budge it like a few millimeters.

vobopl

Any chance you are using eccentric BB or hub and it is rotating at the wrong place?

skelly

nope

skelly

the chainring seems a little loose on the spider. the bcd is a perfect match though.

the homealien

If there's a truly large difference in chain tension, you might just have a bent chainring, crank spider, and/or bottom bracket spindle. If that is the case, no amount of chainring-centering will do you any good Check to see if any of those are bent.

skelly

yeah that was my next thought. spindle looks perfect so then i thought it might be a bent spider arm or something. but spinning with the chainring off and something right next to the spider arms for reference looks like the spider is fine too. the chainring worked 10 hours ago so i don't think it's that. boggles the mind!

if i hold my finger next to the teeth of the spinning chainring so they are just barely touching, the teeth pull away from my finger about a mm for about a 1/3 of the rotation. and by 'away' i mean toward the center of the ring not sideways.

i'm going to try another chainring just to rule that out. thanks for the suggestions.

skelly

diff chainring works fine. i can't see anything wrong with the other one and it worked find yesterday. i don't know what happened to it...

thanks for the help guys.