HELP!!! Chain slipping with all new drivetrain

stully05 said:

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.

is the chain "slipping" as in scooting over several cogs at once when you apply power or is it "sucking", ie getting jammed into the chainset. it could be the case that the chainline of the new cranks is different to how it was before.

if it is shifting ok it won't be the rear mech.

assuming that it is slipping NOT sucking...
when it slips, does the casette move at all? (ie is the chain scooting over the cogs or are the cogs turning but not transferring into the freehub. if the latter the freehub body is shot.)

another thing i have just noticed from reading your post is that you previously used an HG53 chain. are you running a 9spd, 8spd or 7spd setup? make sure the equipment you are using is consistant. I would expect a new XT chainset to have "narrow" chainrings. make sure that you have a 9spd cassette and are using a 9spd chain. if you are using an 8spd or 7spd chain this may be causing your problems. (I can't remember whether 8spd is narrow or wide)

Your Rear Derailer Cable has stretched. tighten it up with the twist knobs
on either end