[Summit]

I'm at my wit's end. So I'm not super experienced with chainguides, but...I have a Mini Me on my AS-X. The thing shifts perfectly, rides well. BUT when I freewheel and/or backpedal in a larger cog (smaller gear), the chain jumps off the large cog into the middle cogs, then the derailleur freaks out and the chain hangs up and just screws up the whole mess.

I thought it might have been b/c the top roller was grabbing the chain too much due to my having installed a 36-tooth ring (Mini Me is only rated for a 34t ring). So I changed it to a 32...no luck. It's pretty obvious the inner plate of the chainguide is dragging on the chain when it's in a large cog and pulling the chain off the cog it should be on. What I don't get is I had the same setup on a Big Hit and never had this problem. Stupid bikes...anyone have experience with this or ideas?

 

[Repack]

Sounds like a chainline issue. Rubbing is a different issue. To keep mine from rubbing I bent the tip of the plate a little. I once had an issue of the groove in the roller holding the chain in the wrong position. Can't tell without pics though. Is the groove in the roller off-set? Maybe try flipping it. I once filled the groove with electrical tape as a short-term fix. If the only thing that changed about your setup is the addition of the guide then I would say almost certainly that it is the chainline.

 

[Brian HCM#1]

Yep, most likely chainline, what length BB are you using? If its a 113, go up to a 118 spindle, unless its an E-type BB.

 

[Repack]

Yep, most likely chainline, what length BB are you using? If its a 113, go up to a 118 spindle, unless its an E-type BB.

I think its the other way- the chainline is too far away from the centerline of the bike and that is why it is being dragged down the cogs when he back-pedals.

 

[RhinofromWA]

Could his hub be dragging? I guess if he doesn't notice it enough while coasting it wouldn't be a problem.

Just tossing out ideas.