Mountain Biking - Chain dropping on climbs

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euphoria
07-04-08, 04:54 PM
It only seems to happen when my cadence drops below 60 on climbs

Generic shimano crankset with alivio components

I am a big dude, could the crank be flexing the chain off the ring?

I was sent on a rather painful journey back down the climb this morning.

kenhill3
07-04-08, 05:09 PM
I take it that it is dropping off the granny?

Shifting to the little ring often needs a little finesse- don't do it under load; but on the other hand don't let off the pedal pressure suddenly and slam the shifter (also helps to NOT be spinning wildly).

Also check adjustments. Front derailleur limit may be set too low (too far to the inside). Middle ring indexing may be set too far to the inside.
euphoria
07-04-08, 05:41 PM
hops off the middle ring to the inner also (which also makes me hop off)

usually the gradients catch me by surprise so I don't even shift and just mash

kenhill3
07-04-08, 07:17 PM
hops off the middle ring to the inner also (which also makes me hop off)

usually the gradients catch me by surprise so I don't even shift and just mash

Try the adjustments I suggested.
euphoria
07-04-08, 10:42 PM
alright, thanks.
DirtPedalerB
07-05-08, 01:02 AM
could be a sligthly bent chain or a bent tooth or something, just check it out. If it's not rubbing the derailer I don't see how a front derailer adjustment would make a difference.

If your shifting to the granny while climbing , it does require finesse as stated before... they will all jump off on occasion if your mashing and try to dump it to the small ring.
EatMyA**
07-05-08, 01:09 AM
could be a sligthly bent chain or a bent tooth or something, just check it out. If it's not rubbing the derailer I don't see how a front derailer adjustment would make a difference.

If your shifting to the granny while climbing , it does require finesse as stated before... they will all jump off on occasion if your mashing and try to dump it to the small ring.

+1 on the bent chainring or chain. stiff link maybe?
euphoria
07-05-08, 01:43 PM
it's pretty much a brand new bike...links are all soft and rings are straight but the chain was virtually dry

I still want to pin it on crank flex but i'll take it back to the shop anyway

when I first mentioned it he told me to just take it easy on the bike since he knows I race, but these rides are pretty relaxed