Originally Posted by
jccaclimber
Looks like I'm a late arrival to this thread, but I'll throw my 2 cents worth in:
1. Yes, pedal extenders are going to exacerbate this issue. No, larger pedals instead won't help. It doesn't matter if it's a small pedal on a long extender or a large pedal on no extender if your foot ends up in the same place anyways.
2. It's the NDS (left) arm each time because the left arm to spindle interface sees bending load and drive torque from the left pedal at the same time. The drive side crank to spindle interface sees this torque as well, but not at the same time as it sees the bending load from forces on the right pedal. Right pedal torque about the spindle goes out the sprocket, not onto the crank. TLDR, the left side has a harder life.
4. While you shouldn't really need loctite (unless specified originally), I'd consider blue. I wouldn't use red. If you're breaking loose blue loctite in this application something is already wrong.
Thanks for all that detailed info. 1. yes that is obvious to me (now), physics is physics, leverage is leverage. 2. As you noticed the most recent time was DS. 4. The current broken crank is on with blue loctite, I haven't tried yet to see how hard it will be to get off. I'm not sure I have the tools to remove it destructively if necessary, but it certainly isn't worth saving. I'll take off the chainring and keep it, but atmo I don't have another crank with the same BCD.
My hope is, if I can get the Surly Mr Whirly back on, with no pedal extenders, it will be solid for me, even though I had worked the left crank off it before (with/because of the extender)
If anybody knows of a PT regimen to straighten duck-feet, I'm interested.