Chain skip on jockey wheels

[logdaddy]

Anyone had similar, old Colnago with Shimano 9 speed (sorry !) 105 mech, tacx jockey wheels, 34/48 front and 14/25 rear with a wipperman connex 900 chain. Only happens under load and only in the 34 ring, never the 48 and on most sprockets.

Chain is new and tried a new cassette but no joy, next change is the jockey wheels.

Checked chain length and b screw, both fine, any ideas ?

Cheers

 

[carlrh]

just a thought you do have the 9 speed version not the 7/8 or sram version?

 

[logdaddy]

Re:

Yes, I do have another Tacx set but am going to try the Shimano ones I took off, if I can find them...

 

[logdaddy]

Chainsuck ! found and tried the old shimano jockeys, just the same, couldn't figure out how the slack part of the chain was jumping but watching it at slow speed I could see the chain bouncing. Must have been just enough wear in the ring to hold the new chain, had a spare 36 ring which solved it. It might have settled down but new ring time.