No amount of rear derailleur limit screws and cable tension adjustment fixed this. hanger and derailleur seems aligned enough, and the cassette and chain are not worn either. (Vuelta Corsa crankset and Sunrace 8 speed cassette and chain). Would changing to Shimano cassette and chain fix this problem?
Gear shifts down when backpedaling. It ONLY happens in this specific gear (50×21).
byu/CoffeePanzer inbikewrench
by CoffeePanzer
4 Comments
no, just don’t back pedal. There’s no use case on the road where you’d need to.
It happens because of not straight chainline in that gear configuration. In general try using first half of the cassette with smaller chainring and 2nd half with bigger to maximize drivetrain lifespan. And don’t pedal backwards much, that’s not BMX.
Limit screws are just that, they ONLY limit the extents of the derailleur travel.
A derailleur will guide the chain onto the cassette from the bottom when pedaling forward, when you pedal back there is nothing guiding it except chainline. If you hit all your gears otherwise, then there is nothing more you can (or should) do. Just don’t pedal backwards, or know that it may skip if you do.
It shifts up to a higher gear. You tourn the barrel adjuster 1/4 to 1/2 turn out to get more tension on the cable.
Or just re-index gears from scratch.
But that will just work if derailleur controlling chain. And that happens only when going the other way.