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Ken Braatz
11-25-2002, 11:53 PM
My chain is popping off the chain ring at the most inoppurtune times -- such as on my way up the opposite bank of the stream I just crossed... Man! that water is really cold, glad I was able to clip out before I fell in.... kind of inoppurtune.

It seems to jump off in situations where I ride through some type of depression or any kind of drop in general and always when I'm on my way up and out. It's not all the time, but enough to warrant me posting here.

My bike is a Trek hardtail w/stock SunTour crankset, LX rear der., SRAM cassette, SRAM chain.

Any ideas??? Is it the hardware or am not riding this type if terrain properly?

Thanks!
KB
Rotifer
11-26-2002, 01:00 AM
Well, some part of your drivetrain could be worn out - or all of it. Does it happen whenever you apply lots of torque?
Ken Braatz
11-26-2002, 10:12 AM
Actually, the cassette is only a week old, as is the chain. The rear der is a month or two old. The crankset is original.... 4 months old. I only have 1400 miles on the bike total.

The problem has been occurring -- even before I replaced the cassette and rear der.
Ken Braatz
11-26-2002, 10:15 AM
Sorry, I forgot to answer your main question....

No, it doesn't happen under torque. Only on a moderate hit while pedaling, such as when I need to get up a stream bank.
riderx
11-26-2002, 12:00 PM
First, check to see if your chain is too long. Second, could be worn chainrings. Mixing and matching new drivetrain components with old stuff can do this.
CRUM
12-17-2002, 11:05 PM
It sounds like the crankset. Bent chainring or tooth. Is it a four arm crank set? If so, sheck the arms to see if one is out.

Also, you said the chain was new. Could be a tight link. Check for this by pedaling the bike slowly backwards in the small cog. Watch the chain as it runs through the pulleys. If you see it jump, note that link. Now wiggle it back and forth to loosen it up. Or take a chain tool and slightly move the chain pin from both sides to re-align the pin in the roller and plates.
Rotifer
12-18-2002, 02:01 PM
It sounds like the crankset. Bent chainring or tooth. Is it a four arm crank set? If so, sheck the arms to see if one is out.

I once had a sliver of metal that peeled off a ring tooth that caused a similar problem - just file it down. I also lost a chainring bolt in a race a few years back, this will also cause the chain to pop off.