I need experienced help...weird issue

[mammajama83]

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

[buckybux]

Sounds like you have what we call chain skip. It occurs when the rear cassett gets worn by using old chains. Replace the cassett and the chain and that should fix the problem.

If you replace the chain every 2000 miles, that will keep the cassett from getting worn.

[palewin]

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 ... it really only happens when i ride the bike, it wont do it when i have it in a standIf you have a new chain and an old worn cassette, that would give you the symptoms you describe: chain skips on the worn cogs, but only under tension. If that's the case, you need a new cassette.

[lks]

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
One of the hardest problems to diagnose, even if you used understandable terminology and the relevant data. Start with specifying casette ratio and ring gear size. The miles on everything that contributes to shifting. Shifters, derailleurs, cassettes, ring gears and cables. If you have shifting problem in certain gears, specify what the cogs are and what ring gear you are in. Chain jumping on cogs is called, chain skipping. On the ring gears, it's called chain suck. They happen most times, when you put a new chain on and you have a worn cassette and/or worn ring gears. There should be no shimmy/slop in the cassette.