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Having some gear issues on my latest build. It's an 11 speed sram setup carried over from other bike. Has a gx derailleur. Only change is a oval front chainring. Gears are sweet as, then suddenly will create problems. Jumping off, crunching etc. I think some of the issue could be derailleur, it's about four years old and seems to have a little play. However, is the chain too short? Seems to be stretching the derailleur to me?
is the chain too short?
I'm going with yes, at least until you post a pic 😉
(if it's a suspension bike, does the wheel movement "pull" the chain too ?)
Can't seem to upload pic. Hang on
Is that pic with the shock fully compressed? If so, I'd say you were just about OK. If not, and assuming that compressing the suspension tightens the chain further, it's too short.
Looks a bit tight plus it'll get tighter as the suspension moves. What's the mech and the rear cassette?
Cassette is sram 10-42 11 speed, mech is sram gx 11 speed. That's as the bike stands, no compression. How many extra links? I first measured the chain by going round biggest rings and adding two links, but does seem a little short
That’s tighter than I’d run a chain even on a hardtail. If your orange has a backwards initial arc of the wheel then you are going to be putting a lot of strain on that chain / mech in the lowest gears.
Ideally I’d let the air out of the shock and find the most stretched position then resize your chain.
I’d normally do big ring to big ring without going through the mech and then add 2 links (4 rivets)in the most stretched position. I’m not sure if the oval makes that more complicated or not.
My oval made only a marginal difference to mech position on each rotation. But I guess it could be the proverbial last straw if the chain is already maxed out.
I did the big ring thing, but only at a standstill. Think I'll add two full links and see
what's the situation in the smallest gear?
That chain looks way too short. If you undo one end of the shock so you can move the suspension all the way through the travel you’ll see how much chain stretch happens. With a single pivot with that pivot position it’ll be a lot.
Well, I added two full links., possibly too much now, as in smallest ring chain is basically straight. On a gentle test it does seem much better though
Is the chain and cassette 4 years old like the derailleur? Notwithstanding the chain length, it's very unlikely a new chainring play nicely with old kit like that.
No, chain and cassette are both relatively new. But they did come from old bike altogether and had no issues at all. I do think it was tightness of chain, as it had over stretched the derailleur I think. I remembered that id had to take tension off and the derailleur clicked, was OK after that again.