Tune sixpack/fastfoot combo

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dalb
Posts: 2
Joined: Sun Apr 17, 2005 5:26 pm

by dalb

Just taken my new Storck CD 1.0 out for its first real spin only to find the left crank arm worked loose after 3 miles.Re-tightened the threaded bolt but the same thing happened again after another 5 miles.Any ideas on how this can be sorted or should I simply use more tightening force with or without a torque wrench?Does any-one have an idea of what torque setting I should use for such a job ?

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mike
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Joined: Tue Mar 18, 2003 9:42 pm

by mike

i recommend using loctite blue on the threads of the bolt, and let it sit overnight. i would use loctite for both bolts.

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jer
Posts: 553
Joined: Sun Mar 09, 2003 8:45 pm
Location: Anchorage, AK

by jer

I recommend you don't use lock tight on crank bolts. It sounds like you have already ruined your crank arm, no sense in ruining your BB too. Check the proper torque for a sixpack. A square-taper should be about 350 inch pounds, but I am not sure if the six is the same. Pull the crank arm and clean everything thoroughly (with acetone if you have it.) Consult the manual to see if you should grease the spindle-crank interface. My hunch is no, but again I am not super familiar with the six pack. (Wether or not one should grease spindles of non spline bbs could easily pull us off topic. Conventional wisdom says no, Jobst Brandt and Race Face make pretty good arguments in favor of.) Reattach your crank, grease the threads of the bolt, and properly torque. Use a Sharpie pen to make a mark on the bolt and the crank so you have a visual indicator if the bolt loosens at all. You can get a silver Sharpie if your crank bolt is black. Nine times out of ten it is not the bolt that is loosening, but the crank arm wallowing out from being ridden while too loose. Go on a ride and if the crank feels like it loosens up check the mark you made on the bolt and crank. If the marks are still touching then the bolt is not loosening up, the crank arm is wallowing out an ever larger hole, and it is ruined.

mike
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by mike

i had a creaking noise with my record carbon crank....but i didn't use loctite blue the first time.....since then i put loctite blue on the bolts only, and haven't had a problem.....i'm not sure how it would ruin the bottom bracket by using loctite.

i know if you use loctite red, that could cause problems trying to get the bolt out at all.

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jer
Posts: 553
Joined: Sun Mar 09, 2003 8:45 pm
Location: Anchorage, AK

by jer

Press fit or interference fit attachments like non-spline bottom brackets depend on proper torque of, in this case, crank bolts. If your crank arms get loose it is not because the bolt loosened up. It is because they were not properly tightened to begin with and the repeated pedaling action caused the crank to "walk up" the spindle a little. Now it can move around and creak, usually causing you to notice it and tighten it up. Since the bolt is now easy to tighten and feels loose, it is easy to conclude that it backed itself out. That is almost always not the case. If you did not catch it in time your crank will wallow itself out and change the shape of the hole enough to never again have a good interference fit. If you put loctite on the crank bolt (even if you are smart enough to not put on too much, and even if you use weaker loctite like 222 or 242) you will forever change the friction of the bolt/spindle thread interface. This will yield all future torque readings when properly torquing crank bolts at best inaccurate, and possibly useless. Not to mention that most people’s tendency when using loctite is to drown the bolt in it which still can cause removal problems depending on your hardware, even with 242 (blue.)

If you put loctite on your crank bolts and it cured the creaking of your Campy cranks, I would hypothesize that you caught the problem before any significant damage had been done to your cranks, and when you reinstalled the crank bolts they were tightened to the proper torque and that is what actually solved the problem

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Adri
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by Adri

I had the same thing happening. After 10K on the first ride I noticed it was loose. Stopped at a garage and tightened it as much as I dared too. After a few K it was loose again. By then I was back home and took a 9mm key with me. It keeps working itself loose after a few K.
It's only the left arm. So what do I do? Find a torque meter and tighten it to the (unknown ) correct tension?
Or do I apply Loctite to it, which you seem to dislike?
Auribus teneo lupum

by Weenie


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