Weird Chain jumping in 4 smallest cogs in rear cassette... super strange.. need help



mammajama83

New Member
Jul 7, 2006
11
0
0
i have a full ultegra set up and i am having problems in my 4th through first largest cogs on my rear cassette, the problem is, the chain keeps jumping and i am having ghost revolutions of the crank, which in turn kills my cadence and momentum, i have checked the rear deraller, and made sure it is right on , and i have examined the rear hub and cassette, now there seems to be a little bit of a shimy in the cassette, but nothing to bad... furthermore, it really only happens when i ride the bike, it wont do it when i have it in a stand, what coul;d cause this, and how can i stop it... thanks



thanks
Phil
 

Bob Ross

Member
Jun 22, 2006
363
8
18
My wife has this problem with her Ultegra rear setup, in the 4 smallest cogs. After 3 different mechanics futzed around with her rear derailleur to no avail, mechanic #4 determined that a cam in her shift lever wasn't grabbing the cable solidly, so that over time and after repeated shifting the cable would "slip", causing the RD to shift when she didn't intend to...or not shift when she really intended to...or half-shift...

Still awaiting final resolution, but it might be worth looking into in your situation.