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So... 2 x 9 setup with a superstar chainguide (similar to Blackspire Stinger guide). Everytime I backpedal more than half a turn in the big ring the chain drops down into the granny ring. Its possibly the most irritating thing in the world.
Any ideas as to a) why and b) how to fix it?
Its tempting me to get a 1 x 10 setup but that means spending more money than Im happy with right now....
dont backpedal? no really - try not to cos its bad practice and if you do lose the chain it could really mess you up (e.g. run up to jumps or tight switchbacks)
doesnt really answer the question but I've had it happen before and then i broke the shifter trying to get it back into the middle ring
I'd always assumed it's to do with releasing chain tension and the chain-line forcing it to move to the left (and then dropping back to the granny) but I cant prove it with science or anything else
I a lot of chain drops and slips when I went to 2x9, even with a chain guide so just went to 1x10...you could just put a big ring back on if its really a hassle and you dont want the cost
Believe it or not, a lot of the drive train isn't really designed for back-pedalling; ramped rings, hooked teeth, etc.. The first thing I'd check is the mech alignment at the chainring but, having said that, my money would be on a sticky freehub.
Learn to pedal forwards, not back. Seriously.
Hmmm, yes not backpedalling would be good I guess, just cant seem to stop doing it!
Sticky freehub? Any more detail on that, was thinking of issues at the front end rather than the back, how would this have an effect?
Freehub - it can cause the top run of chain to go slack when you freewheel which may be enough for the chain to drop off the top of the chainring when you back-pedal.
Sticky freehub would affect as it wouldn't go back and so essentially stall the chain...
When I had this issue it would tend to jam between the chainring and chainstay and then you took pot luck what happened next. Often it would dechain going small>large but be ok the other way round. It was only when pushing the bike backwards in the house I finally found the problem.
Worth a look.
Hmm, had a quick play and freehub seems fine, seems to be more an issue at the bottom of the chainrings raterh than the top, looks like the tension at the top stays fine as the freehub moves.
Looks like its either learn not to backpedal or change to 10 speed, could be an expensice evening.......
It's a result of chainline. I expect it only does it when you are on the top range of the cogs on the rear and the big ring? In which case, you will likely have a similar combination in terms of gear ratio on the smaller ring to smaller cogs.
I had a similar issue, I ignored it and tried not to back pedal or freewheel, I destroyed the freehub on the first testing climb.
If you have a closer look at the wheel on the black spire stinger you'll notice it is stepped. This stops the chain dropping into granny when back pedalling. I suspect your superstar version doesn't have the step or just has a little ridge. This doesn't work. Best bet is to get a stinger