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Old 07-02-20, 12:07 AM
  #36  
Hondo Gravel
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Join Date: Jan 2018
Location: Hondo,Texas
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Bikes: Too many Motobecanes

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Originally Posted by RubeRad
OK, so now with 3 different cranks on 2 different bikes, I have a problem with the left crank working itself loose and falling off.

I know correlation doesn't imply causation, but I think something's going on...

I use 20mm pedal extenders, and I weigh north of 240. Is that too much sideways torque for a left crank?

First case was an FSA crank on a BD Motobecane (I didn't touch the factory-assembled crank), where the left crank was held in by a torqued bolt (40Nm I think)

Second case was a Mr Whirly on a Krampus, with a more normal pair of side-pinch bolts.

Third case is the replacement crankset on the Krampus, also with side-pinch bolts.

Should I ditch the extenders, get even bigger pedals (currently Wellgo MG-1 or MG-3 I don't remember) and try to adapt my out-turned feet?

How far can I tighten those pinch bolts before I strip threads on either the bolt or the crank?
My older Motobecane 2010 the FSA crank would always fall off. It’s was a design flaw so I put lot loctite on the bolt and it held. I finally replaced it with a Shimano CX 50 crank around 105 quality with a Dura Ace BB. Reliable and flawless now. My newer Motobecane has the same FSA Gossamer crank but with a new design and it has been good for thousands of miles. The older FSA cranks are notorious for coming apart in route. I forgot I used the recommended torque on the older FSA and it came apart so I just went by feel and it was better then I added loctite the added pressure trashed the BB I said the hell with this and got a Shimano.
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