Originally Posted by 2manybikes
DO NOT PEDAL YOUR BIKE BACKWARDS. Bikes are not designed to do this. It can be done, yes. But that is a side effect from other design considerations. There is no guide to keep the chain on the sprockets when pedaling backwards. And there never will be.
DO NOT ADJUST YOUR BIKE BASED ANY ANYTHING IT DOES WHEN PEDALING BACKWARDS.
Without a derailleur to guide the chain backwards onto the sprockets the chain may jump off when in certain gears. That has nothing to do with the derailleur. It's normal
in some cases. Like when there is an extreme chain angle.
Without a guide, of course it will jump off. DON'T pedal backwards. Don't mess with the derailleur either.
People. People. People. Bicycle and their derailluers are not some magic thing that should never be touched. Bicycles are relatively simple devices that are easily adjusted and repaired. Sure a bike is not designed to be pedaled backwards but it can be, it's just not productive (unless it's a fixed gear). There are plenty of reason to pedal backwards for up to a full stroke. When mountain biking, if you couldn't pedal backwards, there is a whole lot of stuff you couldn't ride! Try track standing without being able to pedal backwards! If the chain is skipping or ghost shifting to another gear when you pedal backwards there is something wrong with the bike that will show up while pedaling forwards. It needs to be fixed!
Stuart Black