Crank fell off

[droo]

The lumo green gooey stuff?

 

That's Shimano's OEM grease. They like putting it everywhere. Even dollops of it all over my brand new Saint RD

 

Just to add - it's rubbish. 50 bucks at Midas will get you five times as much of something three times as effective.

[patches]

Hehehehe that's exactly the way I do it, never knew about that pin till tonight, looks like I have learnt something new.

 

If you're running shimano cranks and have never known/seen that pin until tonight... I have some bad news for you

[kosmonooit]

Are the splines in the first half of the crank supposed to be rounded like that? Looks like the might be stripped due to loose fitting and it coming off?

 

About the grease, there is a case to be made to coat mating surfaces like this, if only to seal against water penetration and corrosion, and there are other more specific compounds for this purpose. But its personal preference, bit like chain wear gauges.

[Tumbleweed]

Are the splines in the first half of the crank supposed to be rounded like that? Looks like the might be stripped due to loose fitting and it coming off?

 

About the grease, there is a case to be made to coat mating surfaces like this, if only to seal against water penetration and corrosion, and there are other more specific compounds for this purpose. But its personal preference, bit like chain wear gauges.

 

I always lightly grease that part of a bike.

[Caerus]

Splines look good to me, don't think the silver pin is part of the crank, I have stripped many cranks off bikes and never seen a silver pin, perhaps some shrapnel picked up when the crank arm came off on the trail.

As for the build who did it? Would be worried that they didn't tighten the retaining star bolt thingy and the bolts to the correct torque.

I Would perhaps drop by another shop to ask if they would be so nice as to help and quickly put it right.

If not and you need some help drop me a pm ill gladly assist,I have my own way of tightening the bolts that has yet to fail me and I have built 7 bikes so far.

Would give it a good clean and use a degreaser to clean up properly before using fresh grease, also use minimal grease on the splines, just enough to ensure it doesn't bind permenantly.

It's very much a part of the crank, as far as I know,and this was told to me again on Sat at my bike maintenance course that it is a "safety" feature to stop the crank from falling off

[Cuppa Bru]

Kosmonooit, that was my first worry as well, as in the first pic it looks like a good 30% of the spline length is worn down. No one else thinks it's a problem, though.

I also prefer greasing things up to keep moisture out (not only because I'm on LCHF).

 

Cheesed about the crank falling off, but if the splines are hundreds as stated before, then I can turn a blind eye, clean everything up, regrease (sorry for the mess @ next service, JB ) and reinstall.

 

It's impossible to find pictures of the inside of the crank, especially the profile on the inside which looks worn down by me. Checked Google, Shimano website, googled the crank's model number

[Cuppa Bru]

Finally found a pic

 

http://brimages.bikeboardmedia.netdna-cdn.com/wp-content/uploads/2010/05/2011-shimano-xt-3x10-dynasys-crankset-weight02.jpg

 

Doesn't look like the splines go the entire length, but still confused about why mine look as though there used to be splines.

[Meentb]

My guess with the missing splines.

 

The splines are like that to accommodate and simplify the fitting of the crank arm on the bb shaft. It centers it before you actually have to align everything to mesh. If it wasn't like that the meshing can be a bit messy.

 

Just my take on it. Not a pro at bike maintenance. Just seems logical though

[kosmonooit]

Could be, I am not that familiar with Shimano cranks although I do have XT on my pavement warrior and have service BB a few times,I cant recall the splines being rounded like that.

 

Doesn't really make sense to me that they would dumbed down like this for fitting, it's not that tricky to locate and fit a splined shaft in this situation.