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elliptical chainring(4 posts)

elliptical chainringctisevn
Mar 19, 2003 10:45 AM
my ring is elliptical. its like bio pace. its not good. chain tight, no chain loose, no wait chain tight. any thoughts on how to fix/prevent this? Im using a da crank with an ultegra ring so maybe a beefier ring like a qbp engagement ring or some ss specific replacement is my first thought but Ive yet to pursue it further.
re: elliptical chainringBudhaSlug
Mar 19, 2003 10:54 AM
It might not be elliptical, it just might be attached off center. This is actually really common for SS/fixed (no ring is gonna be perfect, but you can usually make them work if they were designed to be round). Here is what you need to do:

1) loosen all 5 chainring bolts. Don't remove them, just loosen them so the ring can move a little bit... maybe 1/2-1 turn from tight.

2) rotate the cranks till the chain is at its tightest point (you can feel this in the chain halfway between the cog and the chainring.

3) squeeze the upper and lower sections of chain together slightly. This will pull the chainring back slightly and get it closer to center.

4) Rotate the cranks till you find the new tightest spot, repeat step 3.

Repeat these steps till it is as even tension as possible, and then tighten all the chainring bolts carefully.

This will put your ring in as centered a position as possible and will hopefully fix your problem. If not, its time for a new ring, I love the QBP engagement rings since they are cheap, non-ramped, and seem to hold up just fine.

Peace and Light,
Are you sure???biknben
Mar 19, 2003 10:59 AM
How far off is it? It can be difficult to get the chainring perfectly centered on the cranks. It's not uncommon for chain tention to vary as the cranks turn.

Sheldon has a blurb about this. scroll down to "Chain Tension".
Mar 19, 2003 11:18 AM
thanks I hadnt thought that through, its probably a bit loose. Ill try remounting the ring. It needs a thorough cleaning anyway.