Locktite on crank arm bolts?

[SCHWINN LOVER]

Always torque a square taper wet - that is with grease, not without grease. My guess is that your bolt was not tight enough to start off with or, you didn't grease the axle before putting on the crank.

 

This bit of advise from JB is probably the most important part of the whole operation imho.

[Bat-ass]

Always torque a square taper wet - that is with grease, not without grease. My guess is that your bolt was not tight enough to start off with or, you didn't grease the axle before putting on the crank.

 

This bit of advise from JB is probably the most important part of the whole operation imho.

Using loctite also achieves this as it acts as a lubricant to the threads while wet and being torqued...

[SCHWINN LOVER]

Using loctite also achieves this as it acts as a lubricant to the threads while wet and being torqued...

Loctite is for the thread but the grease goes on the square so that as the crank gets tightened it seats properly and does not bind before it has seated properly.

I would not use the loctite on the crank!!

[javadude]

 

Buy yourself the Park Big Blue Book of Cycling Repair.

 

 

I actually have it. I guess I missed the section on crank torque settings.

[javadude]

"How much torque are we talking about?"

 

Until your veins bulge and your eyes want to pop out of their sockets - then half a turn more.

 

As the grease monkeys say, after tight comes loose.

[Johan Bornman]

Cool! Now I know this too..... but what of an octo-link BB? My non-drive side came loose over time quite recently. Was it just that it wasn't tightened enough in the first place?

 

 

Non-drive side hey? I'm confused. Nevertheless. Octa-link is Shimano's second biggest mistake. Their biggest is their new oversized-axle hubs, but that's another story for another day. Octalink BBs attached to the right and left cranks through an 8-spline interface, hence the octa bit. The splines were at first too short and weak and were later fixed and surreptitiously called Octalink II - with longer splines. Mechanic's error or simplty too much hot-foot descending, ruined the cranks.

 

Octalink was a flop and Shimano wishes it would go away. If an Octalik crank comes off, it is usually ruined.

 

Here's why. Octalink has eight shallow splines. The crank axle is steel, the crank is aluminium. When you descent with all your weight on the two cranks - the one forwards and the other backwards, you put more pressure on the splines than they can handle and they flex so much that they actually lash. Now viosualise this lash. If the wrong foot is forward when you descent ie. goofy rather than hotfoot, the lash causes the bolt to unscrew. Because the crank isn't forced onto the splines as well as with a square taper, the crank moves off the spline and damages itself.

 

Long story, but I've described it in detail in previous posts. Search under my name for say, hotfoot.

 

Yours came loose because you descended with the wrong foot forward. No amount of threadlock goo will fix that.

[Johan Bornman]

Last year I tightened the bolt a bit too much and could not get the crank off! Had to take a dremel and cut it off the square taper BB!

Tried cycling around to loosen it, hitting it with a rubber mallet but it was futile.

Thankfully I had bought a new Deore crank and the old one had done many K's but I was not happy, I had planned on using the crank on my other bike but ja, the biskit kan like to brake that way four me!

 

Did you use a crank puller? Unless the cran's threads are stripped, I've never seen a crank that cannot be removed with a crank puller.

[Johan Bornman]

How much torque are we talking about? I have always been a bit wary of over tightening the crank, but it seems as though its a pointless concern if the crank is going to tighten up itself anyway.

 

We're talking 40 NM on a greased axle. The point is that too little torque will end up with the crank coming off (witht he bolt falling out first), too much will do, like the right amount, nothing.

 

It is impossible to overtighten a crank to the point where the crank breaks. The bolt wil break before the crank breaks. Try it, you'll be surprised how much it can take.