Backpedalling causes chain drops
Dear bikewrenchers,
I'm having an issue with my drivetrain. When I'm in the big chainring and the three biggest sprockets, I get chain drops. It hasn't happened on the 4th sprocket so far.
My drivetrain is Force AXS with wide 43/30 crankset (on a 68 mm BSA wide dub BB), a force derailleur and a 10-33 Force cassette on a XDR freehub.
Any idea what may cause this and how to fix it ?
Thanks !
Backpedalling causes chain drops
byu/SilveryRailgun inbikewrench
by SilveryRailgun
4 Comments
This happens because you’re crosschaining, and it’s made worse on bikes with short chainstays. There’s nothing to fix here; the rear derailleur jockey wheels are designed to guide in one direction only, when pedalling forwards.
Easiest fix? Don’t backpedal.
Heres the question:
Why are you backpedalling? Stop it, your drivetrain isn’t designed to backpedal.
It’s working fine.
Can’t really tell from the short video but something’s not right and this just makes it more quickly apparent than pedaling forward. Perhaps a sticky freehub? What happens if you put it in a top gear, spin it up as fast as you can and then stop?
I don’t know where people are getting the “pedaling backward makes things explode” conclusion. Turning the pedals backward to apply lube or clean the chain has been standard stuff for forever.
You could reduce your chainline by using the narrow “road” cranks, this would reduce the chain angle in those gears and make it less likely to derail.
But then your chainline would be worse in the gears you actually use to propel yourself forward, and there may be insufficient chainring clearance