HELP!!! Chain slipping with all new drivetrain

[stully05]

Alright, got a brand new xt crankset with a new sram pc 991 chain. As soon as first tried to ride with the setup my chain slipped whenever I had a lot of torque on the pedals when I stood up. I talked to a few people and they said try changing the cassette. Got a brand new xt cassette and still the same thing. I went back to my 1 year old shimano hg 53 chain that is a few links shorter than it should be and I seemed to have no problem. The next ride I broke a link on the old shimano chain and just decided to buy a new shimano lx chain thinking that all shimano would be best. well the new shimano is on and....it's slipping! I had someone suggest that readjusting your rear derailuer can sometimes help. I did that and everything shifts perfectly both front and rear. Any suggestions?? I didn't have problems until the new crankset was installed. Is it possible that something could be wrong there? I consulted the crankset manual and it appears to be installed correctly. Can there still be something wrong with my rear deraileur even if it appears to be in-line and shifts with no problems? any advice would be appreciated. I also took it into the shop and had one mechanic suggest the freewheel but my rear hub is only 6 months old.

 

[artmichalek]

Have you tried taking a few links out of the new chain to get it down to the same length as the old one?

 

[AKTed]

Usually slipping when a new chain is installed is because of a worn cassette or worn chainrings, but you've replaced them all! The only thing I can think of is a stiff link in the new chain, but you've had it happen with two different chains! And if it is because the chainline is different in the new crank, then why did the slipping go away with the old chain? Possibly the chainline is a little different with the new crank and the newer, latterally stiffer chains are more sensitive to it than the old chain. Does the slipping happen in just certain chainwheel/cogs or pretty much any combination? Sorry I'm not much help. Good luck!

 

[mikesbytes]

These kind of problems can be quite annoying to track down. I'm assuming that the replacement set included the cassette.

Exactly what type of slipping is occuring? Is it jumping or switching to another gear? Is it happening in a particular gear(s)?

 

[stully05]

IT'S FIXED!!! Add this one to your list of things to check when there is slippage. I had my rear skewer a little loose for the past month or so and those bolts that screw into the hub to hold all the bearings and the actual freewheel mechanism had come a little loose. That gave a little play whenever I tourqed on the pedals and possibly the whole wheel and frame could have torqued too with the loose skewer (carbon seat stay). So I tightened all that up and not a single problem during a long ride where I was really mashing the pedals. Too bad I decided to not go to a race today because of this ****.

 

[artemidorus]

IT'S FIXED!!! Add this one to your list of things to check when there is slippage. I had my rear skewer a little loose for the past month or so and those bolts that screw into the hub to hold all the bearings and the actual freewheel mechanism had come a little loose. That gave a little play whenever I tourqed on the pedals and possibly the whole wheel and frame could have torqued too with the loose skewer (carbon seat stay). So I tightened all that up and not a single problem during a long ride where I was really mashing the pedals. Too bad I decided to not go to a race today because of this ****.

Sounds like you're talking about the hub bearing cones and locknuts (unless you have cartridge bearings). Are you aware that you can overtighten these and destroy the bearing? (The freehub body, by the way, is not held on by the cones and locknuts on a conventional rear hub, although they need to be removed before the freehub body can be screwed off).

 

[mikesbytes]

Mate you should be a bike mechanic with detective work like that! I would of put it in the shop and said "fix it" and then insisit that the mechanic ride it home and back to the shop [instead of his own] the next day just to make sure.

Better take artemidous advice and make sure its done right.

 

[stully05]

Sounds like you're talking about the hub bearing cones and locknuts (unless you have cartridge bearings). Are you aware that you can overtighten these and destroy the bearing? (The freehub body, by the way, is not held on by the cones and locknuts on a conventional rear hub, although they need to be removed before the freehub body can be screwed off).

Could those locknuts being loose enough allowed enough play in the whole rear hub assembly to allow the freewheel thing to slip off its own gears during periods of high torque??? (It is a shimano xt 760 rear hub) when it comes to bb/cranksets and the rear hub I know very little.

 

[artemidorus]

Could those locknuts being loose enough allowed enough play in the whole rear hub assembly to allow the freewheel thing to slip off its own gears during periods of high torque??? (It is a shimano xt 760 rear hub) when it comes to bb/cranksets and the rear hub I know very little.

Clearly, as the problem went away when you tightened them!
If they are loose, then the whole wheel (and freehub), rather than just the freehub, can move around in the frame. You might notice less brake rub, more precise braking and a tighter ride generally since you fixed the problem.
A word of caution; the bearing cone should be hand tightened till it stops and then backed up 1/4 turn. It is then locked in place with the locknut, being careful not to turn the cone on the axle. This allows some bearing play that is then removed by skewer tension. If you don't do this, the bearing WILL pit and destroy itself, sooner rather than later. Have a look at this:
http://www.parktool.com/repair/readhowto.asp?id=105

 

[DOUGEG]

Stully man, sup? take it to the shop.