Help!! 11T casstte setup is sending me insane
Discussion
In building the Ribble up I've gone for a 11 - 28T casstte and all is fine except for gears 10 and 20, where the chain is being lifted up by the cog. If you keep the cadence steady, 9 out of 10 times it works fine, as soon as you increase the chain starts jumping. Watching it on the stand, I've figured out that the teeth on the 11t cog don't always line up with the hole links in the chain,and are advanced slightly, so are picking up the edge of the pivots.
If I wrap the chain around the cog, everything fits, just not when the rd is involved, every other gear is fine, and all 20 index prefectly.
I'd like to get this figured out as its annoying me and when riding I forget about it, leading to some very loud nasty noises, and the LBS can't fit it in for 2 weeks.
In the pic below, you can see a tooth lifitng the chain, just behind the mech hanger.
If I wrap the chain around the cog, everything fits, just not when the rd is involved, every other gear is fine, and all 20 index prefectly.
I'd like to get this figured out as its annoying me and when riding I forget about it, leading to some very loud nasty noises, and the LBS can't fit it in for 2 weeks.
In the pic below, you can see a tooth lifitng the chain, just behind the mech hanger.
Edited by Celtic Dragon on Sunday 6th July 14:19
Sounds just like an indexing issue. Take the gear cable out / off. Set up the 11 tooth using the lower stop screw. Then manually push the mech to the largest sprocket , check it works on that stop. The refit the cable and try that. Remember that the mech, when on the smallest sprocket, the cable will have a miniscule bit of slack, which the shifter will take out on the first shift.
HowMuchLonger said:
piccy no work
Fixed that, thanks for pointing it out, worked in preview 
Looking at the pick now, it looks like the chians riding on the lock ring too, which won't help. I have an 11t locking on order after finding out that whilst its a Shimano hub, Fulcrum in their infinate wisdom on this setup use a campy lock ring!
Looking at the picture, you may have too much tension on the B tension screw. This will cause the top pulley to pull back and not wrap around the sprocket fully. To see you have indexing correct, the top jockey wheel has float of a couple of mm. When in the sprocket, it should sit central, with a bit of float either side, to allow for , er float LOL
Thanks for the heads up guys. I've taken the RD off completly and redone the settings, whilst now crisper, the jumping is still there. Going to wait until the new lockring is here before trying again as the chain is riding the lockring and not fully seated on the sprocket. Theres a gap between the chain and the narrow bit of the chain between the pivots and the top of the lockring of 1.5mm! Take that depth off the lockring and it would give about 1.5mm - 3mm of clearance, landing the teeth where they should be!
It was the lockring, old one is 38mm face diameter the new obe is 35mm. Swapped them over and the issue has been resolved. Gassing Station | Pedal Powered | Top of Page | What's New | My Stuff