|   I keep dropping my chain from the middle ring | Mr Magoo
Nov 26, 2003 10:13 AM | | It happens alot. Middle ring, larger of the cogs down hill panic stop/slide/crash type stops. I hop back on and the chain is on the bottom bracket. This may have to get worse before I find the cause, but here are some other conditions. The bike has been dialed in nicely for months, now, shifting properly in every way. I can pedal backwards. I replaced the shimano cassette body in the spring because of funkiness when I pedaled backwards. The derailler is a SRAM 9.0 long cage about 4 months old (I keep smashing them). I can't figure what causes the sudden slack and chain throwing. All propositions are appreciated. Thanks a million. amd Happy thanksgiving. |
| Funny, but when I switched from my XTR setup to the 9.0, mine... | Tscheezy
Nov 26, 2003 11:11 AM | | stopped dropping chains and jumping gears when backpedaling. I run a very short chain in general on my 2x9 (22/32/bashring) setup, but the 9.0 just creates more consistant tension than my XTR did somehow, so I have far less backpedal derailment now than before. Everything else on the drivetrain is the same.
Try shortening your chain a few links at a time if you trust yourself not to end up in a big-big crosschain which would destroy the chain (which I can't do anyway with no big ring).
tscheezy |
| Tscheezy, a question.... | alibi
Nov 26, 2003 12:21 PM | | Do you feel like there is an inordinate amount of friction in your 9.0 rear derailleur compared to the XTR? When I backpedal the cranks on the stand, they come to a stop almost immediately; I replaced the 9.0 with an XT and they spin like normal. Pulleys spin freely, chain is not rubbing on the cage; it's almost like the chain (PC 58) doesn't mesh right with the pulleys. Maybe it is just the higher tension.
Any thoughts welcome. Thanks |
| Hmmm... no, everything seems similar friction-wise. nm | Tscheezy
Nov 26, 2003 1:17 PM | | |
| SRAM R-derailler is tension adjustable | Mr Magoo
Nov 26, 2003 5:37 PM | | I have only run the middle tension setting. There are 3 holes for spring tension (like on V-brakes). You access the adjustment by twisting the jockey wheel tension arm like a bayonette mount and it pulls straight out. I just don't understand the compromise with tighter springs. I may try this next. Anyone ever do this? |
| mid ring, larger of the cogs...... | man w/ one hand
Nov 26, 2003 12:22 PM | | should mean more tension on the chain, but the chain is being pulled
over towards the lil'ring & bb by the larger cogs. Shift to a higher
gear when you hit a dh section. This will give you some "pedal" & take
the pull towards the lil'ring off of your chain. May or may not help.
Jus' thinking out loud. I used to have th' same problem, rarely now.
Older & wiser. |
| I've always taken the opposite strategy | Mr Magoo
Nov 26, 2003 5:39 PM | | I try to go bigger cassette on descents to take up more chain. the chain pull theory has weight. I'll try it. thanks |
| If you upshift to the smaller cogs | AK Ken
Nov 26, 2003 8:47 PM | | it gets the derailleur up higher and out of the way of smashing into things, and further away from being pulled into the spokes if the suspension compresses radically.
Ken |
| Yes | Mr Magoo
Nov 27, 2003 9:02 AM | | more weight to change my approach. thanks.
I do think something mechanical is involved as well. this complaint just cropped up. my methods are old |
| I had a chain keep jumping off the middle ring... | Lucky
Nov 26, 2003 4:08 PM | | when I'd hit a bump. Eventually figured out the teeth on the middle ring were worn too much to hold onto the chain if it bounced up and down at all. New ring fixed it. Not sure if this is what's causing your problem, but it's something to check if your rings have a lot of miles on them. Good luck!
Kathy :^) |
| yeah, the teeth look old | Mr Magoo
Nov 26, 2003 5:43 PM | | But the LX chainrings are only six months old. thanks for the input. |
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