Hi, my bike is kind of broken
When i use it the pedal falls of, i foud out that the nut fell of and i put it on again but it keeps falling of
Im thinking about soldering it directly but im not sure i give your advice
Take the nut up to your local hardware store and grab a matching size locknut
They have a little insert that grips on the shaft to prevent it from backing off
Are the threads undamaged on the nut and the bolt? If they're not, replace or repair the threads.
Alternatively, get a lock nut, or pour locktite all over your nut. Not sure how long that last solution will last.
Your problem is not the bolt or the bottom bracket. Check the inside of your pedal arm. Its bent out. So it doesnt matter how hard you tighten that bolt. Its gonna wobble itself loose. New pedal arm will solve your shit, son!
OP doesnt need loctite for this to work. Just replace the pedalarm and remember that sides pedalthreads is opposite. Lefty tighty righty loosy.
Working in a bikeshop for the last 5 years. I havent had the need for loctite yet. And id prefer people dont use it before they bring it to me all f'd up. Just tighten it down good. Itl be fine
That happened to me years ago. I didn't own a socket wrench set at the time and could never properly tighten it enough. It always loosened up during normal use. Once I did get a socket set, I made sure to properly tap on that pedal arm as far in as it would go. Next, I tightened that damn nut on once and for all. Never came off again.
As other anons have said, locknut and the proper socket to tighten it. A quick and dirty method uses a dab of fingernail polish on the threads. That will keep it from backing out and still be removable. Blue threadlock also works but that costs more than nail polish.
this guy^^^ is the most-correct answer so far.
when a bicycle crank nut comes loose, the spindle chews up the hole in the end of the crank, and then the crank won't sit properly on the spindle anymore. It is most likely to just keep coming loose.
You probably need a new crank, and (possibly) a new spindle (the center axle that the cranks turn on). You would have to see if that is damaged or not.