i want to run LHD when i can afford it so i'll stop ruining my chain and sprocket so much. i know you can get LHD cranks, but has anyone tried just swapping round standard cranks? i know theoretically the pedal threads might undo, but do they really? if u tighten them enough? what about modifying the left crank-arm itself so the chainring can be mounted on that side? anyone tried that?
Yes, my friend Nick has been running his Profile Race cranks backwards for at least three years now, without issue. Just make sure to use some Loc-Tite (*note* if you use the red Loc-Tite, and use too much, you'll have to heat up your pedal bosses with a blowtorch to get them off - no joke, I've had to do it with the spindle bolts on my ld Powerbites) and to really torque them down with a pedal wrench. Checking them every one in a while to make sure that they aren't coming loose isn't a bad idea, either.
However, if you're doing this with pedals with a parralelogram-shaped body (ex: Odyssey Jim C, Wellgo MG-1, S&M 101), then the pedals will be backwards (in other words, the back end will taper up, and the front end will taper down, instead of vice-versa), so you'll probably want to swap the bodies of the left and right pedals, so that they're facing the proper direction.