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
thanks
Phil