SLX crank play

[Swany05]

I have done quite a bit of mileage recently and have noticed the lateral play on my slx crank is increasing. 

Both side have an even amount of movement and is no more than a mm or two. 

 

Is this a common issue? and is it a case of simply serviceing the bb?

 

Oh bike in question is a Giant Anthem (2008) 

 

Thanks in advance

[Maximis]

There shouldn't be ANY play whatsoever... Strip, clean, grease and reassemble properly using a torque wrench. If there is still play then perhaps a new bb is needed... Make sure the crank arm is sitting flush with the bb, the bolts holding the crank arm could be loose which will result in the crank arm slipping off. What bb do you have? The old anthems use a press fit I think?!

[Fisan]

There shouldn't be ANY play whatsoever... Strip, clean, grease and reassemble properly using a torque wrench. If there is still play then perhaps a new bb is needed... Make sure the crank arm is sitting flush with the bb, the bolts holding the crank arm could be loose which will result in the crank arm slipping off. What bb do you have? The old anthems use a press fit I think?!

 

A bit off-topic but cranks require insane amounts of torque (relative to seatposts, handlebars, etc.). Most torque wrenches only go up to 10 N.m. Do you get special wrenches for cranksets? (Usually I just tighten the !@#$% out of it.)

[Maximis]

Over tightening will deform the threads, then you run the risk of stripping when you take them off... I have had my entire crank arm slip off during a ride due to under tightening - not a pleasant experience...Chat to your lbs or take it to them. That part of your bike gets the most use so it needs to be done properly

[Alouette3]

Play along the crank shaft itself will be your BB that is shot, very common. If there is play where the crank attaches to the the shaft then the crank is at fault and most likely loose.

 

A bit off-topic but cranks require insane amounts of torque (relative to seatposts, handlebars, etc.). Most torque wrenches only go up to 10 N.m. Do you get special wrenches for cranksets? (Usually I just tighten the !@#$% out of it.)

The crank does not need an ish load of torque. Your cassette yes but not your crank!

You will start stripping the threads if you over torque it, and you will struggle to get the bolts out again. This is at least for a SLX Hollowtech 2 type setup.

[Mojoman]

Play along the crank shaft itself will be your BB that is shot, very common. If there is play where the crank attaches to the the shaft then the crank is at fault and most likely loose.

 

The crank does not need an ish load of torque. Your cassette yes but not your crank!

You will start stripping the threads if you over torque it, and you will struggle to get the bolts out again. This is at least for a SLX Hollowtech 2 type setup.

Apparently not too much with the cassette as it tightens up on itself anyway under load?

[Swany05]

There shouldn't be ANY play whatsoever... Strip, clean, grease and reassemble properly using a torque wrench. If there is still play then perhaps a new bb is needed... Make sure the crank arm is sitting flush with the bb, the bolts holding the crank arm could be loose which will result in the crank arm slipping off. What bb do you have? The old anthems use a press fit I think?!

 

Thank you 

 

Its a BB70 i think, external. The play seems like it is on the shaft and not on the crank arms

 

Ill go have a look this afternnon

[Swany05]

Play along the crank shaft itself will be your BB that is shot, very common. If there is play where the crank attaches to the the shaft then the crank is at fault and most likely loose.

Correct, from what i could see it was along the shaft. 

 

Is it time for a new BB? or just the bearing replacement?

[droo]

A bit off-topic but cranks require insane amounts of torque (relative to seatposts, handlebars, etc.). Most torque wrenches only go up to 10 N.m. Do you get special wrenches for cranksets? (Usually I just tighten the !@#$% out of it.)

 

Shimano cranks only need 12Nm - SRAM cranks are a bit different.

 

OP - you'll need a special spline tool to check tightness on the crank - it could just be that it was incorrectly installed to start with. Shimano BBs usually seize before they develop play, so I'm pretty sure that removing and refitting correctly will sort the issue out.

 

Undo the pinch bolts, remove the plastic preload nut (this is what you'll need the tool for), lift the little plastic clip in the space between the pinch bolts, remove the LH crank, pull the RH crank and axle assembly out, clean, regrease, and reassemble in reverse order. 

 

When replacing, the preload nut should only be finger tight but tight enough to take up any play. If you can't get the play out like this, replace your BB. The last step is to tighten the pinch bolts to 12Nm - you'll need to tighten each bolt a few times since tightening the one will loosen the other. I'm going to guess that this was the step that was missed last time.

[droo]

Apparently not too much with the cassette as it tightens up on itself anyway under load?

 

Nope, that's only with the old school spin on type. On the cassette type the lockring is independent of pedaling forces.

[Alouette3]

No special tool required...

 

 

[Swany05]

Shimano cranks only need 12Nm - SRAM cranks are a bit different.

 

OP - you'll need a special spline tool to check tightness on the crank - it could just be that it was incorrectly installed to start with. Shimano BBs usually seize before they develop play, so I'm pretty sure that removing and refitting correctly will sort the issue out.

 

Undo the pinch bolts, remove the plastic preload nut (this is what you'll need the tool for), lift the little plastic clip in the space between the pinch bolts, remove the LH crank, pull the RH crank and axle assembly out, clean, regrease, and reassemble in reverse order. 

 

When replacing, the preload nut should only be finger tight but tight enough to take up any play. If you can't get the play out like this, replace your BB. The last step is to tighten the pinch bolts to 12Nm - you'll need to tighten each bolt a few times since tightening the one will loosen the other. I'm going to guess that this was the step that was missed last time.

good post thank you 

 

Ill give it bash and see whats what.

 

With the greasing, surely those are sealed bearings right? so im assuming you mean grease the axle?

[droo]

good post thank you 

 

Ill give it bash and see whats what.

 

With the greasing, surely those are sealed bearings right? so im assuming you mean grease the axle?

 

Yep - just a light coating on the bearing journals and the spline.

[Fisan]

Shimano cranks only need 12Nm - SRAM cranks are a bit different.

 

My bad, I was confusing the bolts with the Hollowtech BB - which is in the range of 34.5~49.1 N.m. (Don't worry, I always read the specs on the component /bolt before I go crankin-crazy)

[Swany05]

So i had a quick look last night 

 

Loosened the the preload nut and removed the crank arm, cleaned everything up and put the the preload nut back but paying attention as to how it seats the crank. Tightened the pinch bolts bit for bit and there is no play now. 

 

Is there anyway, once seated correctly, that they could be too tight?

 

Thanks for the advice thus far 

[droo]

As long as you didn't tighten the preload nut much beyond what it took to take up the play you'll be fine. If the play comes back it means you haven't torqued the pinch bots properly.