2023 Specialized Rockhopper expert 1×12 Sram Eagle SX (yes I know everyone hates SX) but having problems when in the lowest 2 gears, if I back pedal or roll the bike backwards it drops the chain on the top side to higher gears. The chain is most centered around 7th gear. It doesn't have any bottom bracket spacers that can be removed, it already has a 6mm offset chainring, and there is no room the space the cassette "out". I can't see any damage to the cassette or derailleur the bike has never been wrecked hard only has around 75 miles on it, and has done this since new but has started getting worse.
Does anyone have any suggestions to make things better? I've considered removing the high gear and installing a spacer behind the cassette to get things lined up better, but I'm open to anything. TIA
by Ok_Cap_5811
2 Comments
Stop pedaling backwards. This is common on mechanical 1x setups.
The chain wants the straightest line possible, when pedaling forwards, the tension from the derailleur helps it in gear, when you backpedal, you release all that tension so the chain will want to fall on to one of the middle cogs.
If you remove tension from the gear cable and move the rear deraileur by hand, can it align correctly with all the required gears? If so take a look for things stopping easy cable movement. It could be a bit dirt of near the internal routing holes, or a bit of fraying cable.