Originally Posted by
lyle.coop
1. It might happen when I'm back pedaling. I'm not sure. I'll try to be conscious of what I was just doing before it derails.
2. @
maddog34 does the chain look too dry? I'll lube it. How do you know I'm shifting too fast? Can you see wear pattern on my cassette rings?
3. It seems to derail somewhere in the middle of the gear range. Definitely not in the very high or very low end of gearing.
4. The hanger should be straight. It's a brand new bike, no crashes. I'll check though.
5. I'll check the d
erailleur hanger bolt. I checked it the first time it derailed. Haven't checked since. I did notice the rear wheel was loose after my last ride. But the wheel was tight when the chain derailed.
#2... "too fast" as in too many gears at once... I've had a shifter in the shop that was going from bigger to smallest every time the release trigger got clicked.. it would derail and lock up the chain when it did so across 3 gears or more.... a pawl spring had failed in the shifter... Not saying that's the exact case with your problem.but dropping too many gears at once can and does cause derails...
Regarding #3.. i've seen a sticky cage pivot cause a momentary slack chain...could there be a ding on that pivot? "new" or not, check EVERYTHING, is my diagnosis procedure... check that lower knuckle and the cage's operation for any resistance other than the spring....
i'm quite serious about those unusually long teeth on those jockey wheels... that stands out as a possible source of trouble.
Check the B-screw adjustment... if it's not correct, the jockey wheel might be out of position relative to the cassette cogs, allowing that annoying derail to happen... i like to align the paralellogram to the incline of the cassette for best operation of the der.... the middle parts of the der. should align front-to-back, or "flat, not leaning" as one buddy says... there are actual B-screw adjustment specs for jockey wheel distance from the cogs...
and lube that chain.. not stiff, heavy wax... use light, oily lube.. I just cleaned a chain last week that was lubed with heavy, sticky wax... it was extremely reluctant to shift until cleaned... it acted like it had a dozen tight links too.. it works fine now....
(To the chain waxer crowd.. we're trying to help the OP stop the derails, not endlessly harp about how long you think your chain has lasted.... There''s an active Waxer thread you can post in... this ain't that thread.. Thanks.)