X9 double chainset - keeps working loose

DickBarton

Hi,

Got myself a new bike and is has X9 10-spd. It's all very nice (although the SRAM rear shifter doesn't have a positive click and I keep overshifting - I'll adjust to that!) but the chainset keeps working loose...it gets bolted on with a 10mm allen key (not always a size I carry in my bike bag!) and it needs to be torqued to about 45lbs/ft so it says on the bolt head...

So I've tightened it up and all is well, but it's worked loose about 8 times now...anyone else suffered this and what did you do to remedy it?

I was thinking of some Loctite on the thread and then torque it to the required setting...but not sure if that will be enough to hold it as I'm sure the pedalling force will no doubt put extra 'stress' on it and it will work loose again.

Cheers.

johnsav

loctite isnt needed..
I'd take it back to the shop and let them worry about it personally.

njee20

45 ft/lbs is chuffing tight, are you sure you've done it up tightly enough?

cooldad

Or overtightened and stripped something.

njee20

Unlikely, it really is just one pinch bolt done up f-ing tightly!

I never had my XX cranks come loose I must say.

bails87

Same, I had a GXP crankset on my Boardman too, just always did it up really, really tight, and never had a problem/

DickBarton

Ok, I have a torque wrench but currently no way of attaching the 10mm Allen key to it...so it is just me tightening it...will get an adapter and proper head so it is on properly and I can make sure it's torque tight.

Cheers.

stubs

DickBarton wrote:

Ok, I have a torque wrench but currently no way of attaching the 10mm Allen key to it...so it is just me tightening it...will get an adapter and proper head so it is on properly and I can make sure it's torque tight.

Cheers.

Shouldnt that be an 8mm key the cap with the 10mm keyhole is just there for the crank bolt to push against so the crank self extracts. Its the smaller key hole you tighten up to pull crank on.

DickBarton

Hi,

Nope, definitely a 10mm allen key. The bolt says 48-54 N-m or 425-478 in-lb - and the torque wrench I have doesn't go high enough....so looks like it needs to go barsteward tight...and then some!

I'm guessing the bolt just hasn't been torqued to the right setting and just needs to be tightened correctly - that is based on the fact my torque wrench doesn't go high enough and it's a standard bike shop issue so suspect it won't have been done tight enough when first built.

Also looking at the SRAM guide - http://www.sram.com/sites/default/files ... nksets.pdf - and looking at the Press Fit 30 install, it also gives the torque settings and the allen key size needed. Thing I've not worked out (as I've not removed the chainset yet is whether or not the other side of the crankset (non-drive side) has an allen key fitting on it as well...if it is circular and the 10mm allen key passes through then I could use the 10mm key I have and get it fitted to my torque wrench (even to ensure it is done at least as tight as my torque wrench can go!.

bails87

Thing I've not worked out (as I've not removed the chainset yet is whether or not the other side of the crankset (non-drive side) has an allen key fitting on it as well...if it is circular and the 10mm allen key passes through then I could use the 10mm key I have

I'm not sure what this means.

SRAM cranksets have one bolt, with a larger extractor cap over the top of it. On the non-drive side. Do the bolt up flippin' tight.

nicklouse

DickBarton wrote:

Hi,

Nope, definitely a 10mm allen key. The bolt says 48-54 N-m or 425-478 in-lb - and the torque wrench I have doesn't go high enough....so looks like it needs to go barsteward tight...and then some!

I'm guessing the bolt just hasn't been torqued to the right setting and just needs to be tightened correctly - that is based on the fact my torque wrench doesn't go high enough and it's a standard bike shop issue so suspect it won't have been done tight enough when first built.

Also looking at the SRAM guide - http://www.sram.com/sites/default/files ... nksets.pdf - and looking at the Press Fit 30 install, it also gives the torque settings and the allen key size needed. Thing I've not worked out (as I've not removed the chainset yet is whether or not the other side of the crankset (non-drive side) has an allen key fitting on it as well...if it is circular and the 10mm allen key passes through then I could use the 10mm key I have and get it fitted to my torque wrench (even to ensure it is done at least as tight as my torque wrench can go!.

Bike shops dont fit cranks to new bikes unless it is a custum build. Yes they do have the required kit.

What tzpe of crankset is it GXP? GXP pressfit? BB30?

rvokes

I have/had the same problem with the x9 bb30, it just needs to be on f.tight, the left hand side locks up ok, the right hand side is a cow to do properly, but i ended up getting it to lock by brute force, and it hasnt come loose since... :-D

DickBarton

Thanks for the advice rvokes...it's the driveside crank that is working loose...attached to the bottom bracket.

I'll just do it up real tight and see how it goes as it sounds that what you have done...thanks.

nicklouse

right so it is a BB30 crankset.

you are backing of the preload collar first?

you are seating the crank before trying to set the torque?

you are then setiing the preload and locking it?

Anonymous

And you're absolutely sure on the BB, i.e. it's a Press Fit 30?

That and BB30 are 10mm, but all the rest of the SRAM/Truvative stuff I think are 8mm with 10mm surrounding nut (that you don't touch!).

Loctite is no use at these high torques. If anything you should use copper grease on the threads to help undo the thing when it seizes.

Torqued correctly it should be fine. Guess you've got the low torque wrench, which is no good for high torques.

I'd pop into the shop and get them to do it correctly, and show you what torque is required. If you're not sure how tight there's nothing worse than over tightening. If you can get an idea of the force required you can do it without the wrench yourself later (or just buy the high torque wrench).

p.s. more detailed manuals for SRAM or Truvativ branding as appropriate...

http://www.sram.com/sites/default/files ... -rev-a.pdf
http://www.sram.com/sites/default/files ... -rev_1.pdf