mountain bike question

i ride a cannondale prophet and recently when climbing hills the chain keeps jumping out of gear then back to the gear i have selected. its a real pita. it seems to be jumping from the back cassette, mostly on the larger rings. i also find it really happens when climbing hills and even more when im standing and climbing. the teeth on my cassette are definatley worn, but not down to nothing yet. do i need a new cassette, or is something out of adjustment?

 

sounds like your drivetrain is worn out. Go to a shop and ask them to check your chain wear. If it is past 1.0 you are in trouble. That means you need to replace the chain, cassette, and most likely some or all of your front chainrings.

 

im really hoping its just the cassette, i figured i would ask hear to brace myself for damage when i bring it to the bike shop this week.

 

if they end up concluding that your drivetrain is effed, you can try to save some cash by just replacing the chain and cassette. Ride it with the original rings for a while and see if it slips off the front.

 

yea i think i might just try that. the chain is like new, and the front rings dont ever seem to slip. maybe ill just start with a new cassette (looks like a decent one runs about $50) and go from there.

 

Sounds like cassette/chain mismatch or wear or torque issue when standing climbing tweaking chain line. I had an old Diamondback FS bike that would do that when torqued up climbing....or cable stretch and the adjuster on the rr derailleur just needs a twist or 2

 

It's more than likely your cassette. With the tight spacing these days, 9spd and now mountian bikes are moving towards 10spd, things become more finicky.

I just finished replacing my own cassette. Cassette and chains are the most wear items on your drivetrain. Your cassette will last longer if you maitain your drive chain and keep it clean i.e. replace chains when they need to be replaced, and lube.

 

it sounds to me like its the rear derailer. it will do exactly what you are talking about if the adjustment cable is to loose. after a while that cable stretches. It can be tightened by turning the adjustment where the cable goes into the derailer (usually in a clockwise direction)

 

Are you using correct rear sprocket to correct front? I.e. 1 in front and 1-4 in back, 2 in front and 3-6 in back, etch. Keeping chain straight as possible!

 

Check out this link. It helped me a lot when I was having the same sort of problems.

http://sheldonbrown.com/derailer-adjustment.html

 

It sounds like it's ramping. With teeth worn, they definitely will slip down. upon torque, especially when doing climbs. If it weren't doing it under load, then I would say it's a der adjustment. Most likely a combination of both due to the stresses.

But if the teeth are worn that really should be replaced, regardless.

I would say a new cassette would benefit you the most at this point.