I bought a carbon 29er back in March and have been plagued by the chain jumping off the big ring when hammering along on rough terrain.
Could be down to the fact that the SRAM X0 front mech is about 4mm above the big ring as the Direct Mount fitting won't allow it to go any lower.
LBS tried to fix it and even a shorter chain did not help.
I was at Afan on Saturday and the chain jumped and jammed coming down the steps on Darkside so I couldn't pedal or rotate the cranks at all. Fixed itself a few seconds later but a bit scary.
I popped in to Skyline cycles and they agreed that the mech should be a bit lower but it was on the lower limit of the direct mount. They had a DM Shimano XT so I asked if they could fit it as it looked like it would mount lower. 20 minutes later I was off again.
New XT mech shifts way better, doesn't have the stupid cut out on the side plate where I suspect the chain jumps out of.
And the chain didn't jump once for the rest of saturday and sunday. Especially down the the Wall singletrack with loads of braking bumps.
Kudos to Skyline and Mr Shimano.
But....but.....but....THAT'S A DOWNGRADE
*screams*
*jumps out window*
'Shimano.... it simply works', should be their slogan.
To use anything else is folly.
"Shimano... it simply works... about as well as the alternatives within acceptable boundaries involving personal choice and correctly set up bikes"
FIFY
To use anything else is [s]folly[/s] personal choice
and that one fixed for good measure too
SRAM user are you..?
Oh! touch a nerve did I. lolsss
Could be down to the fact that the SRAM X0 front mech is about 4mm above the big ring as the Direct Mount fitting won't allow it to go any lower.
LBS tried to fix it and even a shorter chain did not help.
By adding in this bit it shows that it was never going to be right in the first place. You come here to spout anger over ill component choice and make yourself feel better by putting a brand down that you haven't chosen/set up correctly in the first place.
Now from me,some might think 100% Shimano all the way,I have to stand up for Sram here. I use a XX front mech on the 2x10 XO chainset on the 29er and it shifts sweet. Not keen on their shifters and rear mech's but I do get on fine with the above.
SRAM X0 front mechs on both bikes > no issues here! (one is a direct mount, the other a band mount)
People are reading the original post and picking things up all wrong. If it was the right selection and fitted correctly.. then he may have had no issues.
If it was a case of this then I too would be spouting how Shimano is fit & forget but its not.
As much as I'd like it to be, its not ;O)
My bike is a Whyte 29er CS, bought as a complete bike and I'm disappointed that there was no room for adjustment. Considering that the front mech and chainset was chosen by Whyte. You are probably right in that it was never going to work properly.
I did a search and there are quite a few people complaining about the chain jumping off the outside ring with 2x10 setups.
http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/issues-2x10-chain-drop-669708-2.html
This is my first 2x10 setup and I suppose the difference is that I was riding hard on the big ring whereas I would have probably been in the middle ring on my old bike.
Perhaps it's the frame that's rubbish
I've got an X9 direct mount mech, and when I took it off (to clean all the Swinley mud out of it) there were a couple of spacers/washers between the mech and the frame..... I know this because they dropped out and rolled under the sofa.
Is it possible that Shimano/SRAM are using slightly different direct mount standards? And yours came with/without a spacer by mistake?