Hey all, I have been having an infuriating issue lately with my daily rider. Every few days (probably 10-20 miles total, it's a commuter bike) the non-drive-side crank will start to feel loose- I start to notice it when the pedal spindle shifts at the top of my pedal stroke, then when I pull over and check the crank i can wiggle it in and out on the bb spindle- not forward/backward, but in and out from the center of the bike. It's been happening so often that I've been carrying a 14mm thin-wall sprocket wrench in my bag to tighten the bolt, but it always comes loose again. Used to happen every several days, not it's happening every day. The cranks are Sugino and the BB is Shimano... are they the same taper? I feel like it's not a taper problem because the drive-side crank is solid as a rock and always has been.
So here's the question: is it just a ****ty crank bolt that's rattling loose? Could I stick them back in with some blue loctite to solve the problem, or could something be screwed up on the threads on the inside of the bb spindle? How much damage could this do to the BB, would it be worth replacing the BB/cranks? This is seriously driving me crazy, thanks in advance for the help!