So.
I’ve been running SRAM Eagle GX AXS on my Specialized Epic Evo for more than 2 years, with no problems at all. In fact, hugely impressed.
However, of late I’ve run into issues where the chain falls down the cassette if I’m in the largest sprocket/cog - this doesn’t happen under load but particularly happens but if back pedalling. There are no problems with shifting in either direction and this tends to be a problem on steep techy uphills where I might back-pedal half a rev, or more likely when trying to get going again having botched the first attempt (usually on a semi-technical ascent).
I can’t work out if this is a problem of chain length (which seems odd, since this is a newish problem) or something else.
Replaced the chain to make sure there was no wear issue causing it.
I’ve cleaned the whole drivetrain and checked that there’s no issue with the freehub - it seems absolutely fine.
Any suggestions?
Cheers
Worn out cassette? Bent hanger? Could be a myriad of things so why not just take it to a decent local bike shop.
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Yeah. Common problem. Pedaling forward, the derailleur pulleys guide and keep the chain on a cog. Pedaling backward, there’s nothing to do that. On the largest cog, the chain line angles outward toward the chainring so when backpedaling there’s a tendency for the chain to move outward to smaller cogs. Chainring teeth are long and designed to retain the chain no matter what, but cassette teeth are short and made to facilitate shifting, so by design don’t retain the chain very well. I find that a new cassette and chain do better then worn ones in the respect. If the RD cage spring has weakened, this can contribute to it as well. In my riding, it’s generally nbd as the max I backpedal when ratcheting over obstacles is less the 180 degrees at the crank, which is even less that that at the biggest cog, so if the chain drops to the next smaller cog, it’s only for a fraction of the next pedal stroke.
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