Alright guys,

It seems that I have worn the splines in the non-drive side crank arm of my SLX cranks. Now when i slide it onto the splines on the spindle it doesn’t fit snugly, it has some side-to-side play in it.

If i do the plastic crank cap and the pinch bolts up as tight as i can the cranks feel tight and secure, as they should. but they inevitably work their way loose after a short while riding. Any one got any cheeky tricks or tips to solve this problem (even temporarily). Or is it going to be buy a new crank arm/crank set.

Cheers!

how have the splines become worn? were they fitted correctly?, if they were then i’d be looking at sending them back to shimano if they are still in warranty?
are you using the right amount of spacers?

Happened to a mate of mine after he had ridden for too long with loose pinch bolts, the cranks could rock back and forth slighty and wear the splines.

Think he had to buy a new L/H crank in the end.

It doesn’t sound good, do you have any play in the bearings?
You could get your LBS to have a look, they might spot something & be carefull you don’t strip the pinch bolts if you’re doing them up that tight!

SLX Replacment LH Cranks

SLX LH Cranks

Cheers for the replies. They were all definitely fitted correctly and the BB bearings are all good. I have been using them hassle free for almost 2 years, but i think i went for a ride a couple weekends back and they werent done up fully and thus the splines have worn.

I had seen that replacement crank arms were available, but i dont really want to accept the consequences of my mistake and spend more money 😛 But its looking like that may be the only real way to fix them.

Hey, how badly worn are the splines and have you tried thread locking the bolts?

You might need to replace the crank or parts of it, I do a repair on the diabolus cranks where I fit helicoils and install grub screws. What size BB do you run?

Before I forget I have some cranks lying about, nothing special but if you tell me your BB size I’ll let you know what’s there. I don’t really need them and just think of them as just, getting rid of them is fine by me!

I have some 2004 HTII XT cranks, so probably exactly the same as your SLX. I recently damaged the spline on the none driveside crank arm when it slipped (presumably not tightened up properly). After that, the crank arm kept working loose no matter how tight I tried to pinch the bolts. A new 2004 matched crank arm cost me £60. You can buy an alloy preload screw on ebay to replace the plastic one, which might hold the crank arm on, but probably not. So, then you have to decide whether to buy a new crankset or replace the crank arm. I replaced the crank arm, but now think it would have been money better spent if I’d spent a bit more and replaced the whole thing for new. You can buy 2nd hand on here or ebay at a good price, but might possibly be buying something that has the same problem (or a pedal thread being shot) unless you can be absolutely sure of the reason for the seller selling ie check the pedal threads and spline being in perfect condition.

I have a raceface diabolus crank that I’ve modified to run grub screws as it had play.

I would be happy to give it to you, if you tell me how you get on with it and if it works.

I’ve been running one on my commy for about 6 months and it’s been fine.

😀

If you do the crank cap up tight you’ll just knacker your BB, and the cap will probably snap when your crank comes loose again.

I would try using some loctite 643 on it.. At leastI think it’s 643.. it’s the one for holding studs and bearings in.
Degrease the crap out of everything and get a good smear of loctite on the splines, inside and out.. you want to fill all the gaps. Clean any off the cap end thread and put the cap back in with grease. Only do the cap up thumb tight. Do the pinch bolts up as normal, and then leave it for 24 hours for the glue to fully harden.

I’ve known this to work with some slightly knackered ISIS cranks, so it’s worth a try.

I had a go at a bodge solution last night: cut a strip of aluminium out of a beer can, matched it to the circumference and width of the splined part on the spindle, wrapped it around the spindle and squeezed the crank arm on over the beer-can-shim, the splines on the spindle crush the soft beer-can alu into the worn splines of the crank arm, thus filling the gaps.

My mate said it might work, i was skeptical, but after 20miles around the long mynd today my cranks are 100% wobble free. Not sure how long it will last, but if its until after xmas when i should have some money to buy a new crank arm/crank set then i will be happy. 😀

cheers for the offer kaesae. i will let you know if my solution fails! 😀

Ace bodge!

I’d avoid long rides tho…

Have you used thread locker on the pinch bolt threads?

£45 for a LH crank arm on CRC