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Discussion Starter · #1 ·
I have a Tru Vativ crank set on my V-3.

I have never had this problem before with it, but today, the damn left crank arm started wiggling. I tightened it. About 5 miles later, started again, then 3 miles, then 1 mile. Every time I tightened the hex nut back down, getting tighter with it each time.

Any ideas as to what could cause this? Remedies? Please don't tell me I need a whole new crank.

Peace.
Ben :confused:
 

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Square taper or ISIS?

Proper torque is all you need. But once you put some miles on a loose square taper crank arm, it starts to wiggle around on the spindle and the square taper gets rounded off. Doesn't take much to make it so it'll never stay tight on its own.

Some guy's will slather the crank bolt in Loctite, with mixed results, and others will put a gob of JB weld on the spindle to hold it together (good luck getting that mess off).

If you're only using a 6" allen key to tighten it with, realize that you've got to put 70 pounds of force onto the very tip of that wrench to achieve proper installation torque.

Once you install it with proper torque, experiment with Loctite if it's still necessary. If that doesn't work, I think you know the next step.
 

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All Truvativ cranks these days are ISIS....

On their website, in the FAQ's, they say loosening is most often caused by failing to install a washer between crank bolt and crank and/or not torquing bolt properly (35 ft-lb).
FWIW I had exact same problem and I DID use torque wrench. I didn't have washer on. I do now, and hope I haven't pooched the crank arm. Have to ride it some more to evaluate that..
Have heard of others with exact same problem

FD
 
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