Shimano crank retainer/safety pin thingies

A bit of a random one, this.

A couple of rides ago, my zee left crank came off, just as I was landing a small, but quite fast jump.

As well as needing a new set of underpants, I also need a new one of those crank retaining pins (that hinge on one of the pinch bolts to go into the hole in the spindle).

Unfortunately the incident ripped the pin bit clean out of the plate.

Does anyone know if/where I can buy a spare one of these (circled in red on the diagram):

You do realise it’s just here to tell you that you’ve got the crank far enough into the spindle? I ran the cranks on my DH without one for years – didn’t die once. You’ve already proven that it’s not to keep the crank on 😉

That’s not what should be retaining your cranks. its far too weak, it should be held in place with the plastic retaining bolt that threads into the drive side crank. the big nut pretensions the bearings prior to proper clamping with the two 5mm hex bolts.
its been know that over tightening of the clamp bolts can crush the axle which may have lead to your problems.
I think the little pin thingy should be a last resort, but people are welcome to correct me.

Pin thing will stop the crank walking off the axle, you only get them on cheaper chainsets, I’ve never had one fitted. PITA.

you only get them on cheaper chainsets

Yep, thats right those cheap chainsets like Ultegra, XT, 105…. 😉

I don’t think non-Shimano brands use them and as you’ve proven – it doesn’t do much. They’re not going to do anything and shouldn’t be needed if you tension the crank on the bearins and torque the bolts correctly

Oh well, I’ve only ever had Dura Ace and XTR, except the Tiagra one on the winter bike! 😳

I know XT M760 didn’t have them either. Same category as those tabs on disc rotor bolts and the lock wire on calliper bolts. A fail safe, but entirely superfluous for 99% of cases.

Binned mine 2 years ago and I am alive to type this response 😉

The pin itself is not super important but the plastic spacer is important for not over tightening the crank bolts. The plastic retaining bolt is what hold keeps the crank on the spindle.

The “spacer” isn’t a spacer – if you’re tightening the bolts down that much that its keeping the opposing surfaces apart, then you must be way overtighterning the crank bolts.

There is a clear gap even with the crank bolts tightened and you can pivot the “spacer” down oonce the cranks are properly fitted.

http://www.sjscycles.co.uk/mobile/shimano-deore-lx-fc-m582-security-plate-1fu-9812-prod34907/

Got mine from here

Well if it is then my mistake that it was what a bike mechanic told me at a shop.

Also on the cheap crank thing the current generation of XTR and the previous generation both used the plate.

Was a late addition on M980 then, mine certainly didn’t have them.

It categorically will not stop you over tightening the pinch bolts! You really don’t need it. I’ve never used one in 12 years of Hollowtech 2 cranks, and I’ve not died!

The plastic retaining bolt is what hold keeps the crank on the spindle.

it’s really not

If you tighten up the preload cap ( plastic bit in the end of the axle ) lots and lots to try and keep the cranks on all you do is shorten the life of the bb.

The end cap just needs to be done up enough to stop the cranks having play in them
Then torque the two hex head bolt evenly to aroubd 13nm

That plastic preload cap gets deformed though when the bolts are even slightly tightened retaining the crank arm?

**** me.

Fourteen posts on this thread after my OP, and only one actually answers the question of where I might procure another pin. The rest given over to point scoring and bickering.

Thanks to squiff.

As for all the gubbins above, it is the plastic preload bolt that tensions the cranks onto the bb bearing to eliminate play. Too loose and the cranks wobble. Too tight and you grind the bearings to death in quick time. The pinch bolts hold the crank on. The retaining pin stops the crank walking off the spindles. What it doesn’t do is stop the crank arm flying off when you land at speed.

Anyway, it is slightly ironic of me to wade in as it was my mechanical ineptitude that caused the problem in the first place.