[voithofer]

Greetings,

I just bought a used 05 Prophet. I'm having problems with it skipping gears when I put a lot of pressure on the pedals going up steep hills. When it happens it jumps up 2 to 3 gears (to smaller cogs). I'm trying to figure out if I need to replace the cassette and chain or the rear derailleur (XT RD-750). The reason that I think it might be the derailleur is that the chain (Dura Ace) is within spec. (Well within the .75 mark on the park chain tool). The cassette doesn't appear to be worn a lot but I'm no expert in telling that by sight. I have put a new shifter cable on and have adjusted it so that it shifts smoothly. I have also checked for stiff links and haven't found any. The rear derailleur seems to be quite loose when I move it side to side, but again I don't know what is acceptable. Any thoughts on how to better troubleshoot this would be appreciated.

thanks, rick

 

[Westy]

Sounds like a worn cassette to me. They don't always look worn unless you place it next to a new one.

 

[Quo Fan]

Could also be a bent derailer hanger. That will cause ghost shifting, too.

 

[jonKranked]

Sounds like a worn cassette to me. They don't always look worn unless you place it next to a new one.

might also be the chain. brand new chain + used cassette can also = problems.

And like quo fan said, might be a bent hangar too. Have this checked as well before you purchase anything.

 

[william4269]

i bought a new chain and cassette. when on the top chain ring, it skips. any reason why?

 

[oldfart]

Guys guys go read the op again. The chain skips DOWN the cassette three cogs. A worn drivetrain usually skips in place. The only reason for a derailleur will up shift by itself is the cable slipping or the shifter failing. Unless things are skipping so badly that the chain drops down to higher gears and then shifts back to the original position.

But is the chain skipping, upshifting and not going back into gear? Does it still shift to all cogs? Chances are the seller put old parts on the bike and something is worn out. .75 on the Park tool imho is a worn out chain. I would suggest changing the cassette and chain and posibly the chainrings too. Wouldn't hurt to replace the cables and housing too.

 

[oldfart]

i bought a new chain and cassette. when on the top chain ring, it skips. any reason why?

Worn chainring.

 

[binary visions]

Guys guys go read the op again. The chain skips DOWN the cassette three cogs.

The OP is two years old, I think if he's got drivetrain problems, he's either resigned to living with them or has done something about it

 

[slimshady]

Hmmm... Since you changed the cassette and chain, I would suggest to check the shifting cable/housing. Any of them might be too short, and when you put pressure in the pedals, the cable might get more tension.

 

[ultraNoob]

The OP is two years old, ...

good catch... missed that little detail

 

[oldfart]

Chaaaa. I hate when that happens.

 

[shorerider]

I realize its old but there might be play in the freewheel.