Gecko77

Hello, I am a new user here but i'll get to the point. I am a heavy rider.

I own a 6KU Single Speed bike and the crank arms are square tapered. It's a Neco Square Taper BB. It's been almost a year since I got my bike and I have stripped the square hole on 3 left-side aluminum crank arms and 1 BB bolt.
The drive side has never given me a single problem.


I notice the bolt loosens when I put stress on the crank arms to speed up, or go from 0 to cruising speed. The loosening of the bolt causes play on the crank arm, which then causes stripping.
Not to mention, only when I pedal too hard uphill I hear creaking, but on flat ground there is no creaking no matter how hard I pedal.
I suspect it's my own weight but first here are some other details.

The BB bolt tightens clockwise, so I suspect I am loosening the bolt whenever I pedal, which is counter clockwise.

The M8 threaded bolt has never been tightened to the precise torque by my bike service shop, they tighten it to hell and I can only tighten it so much with a hex key, which clearly will not get me near the proper torque.

I used blue Loctite, let it settle for 72hrs, and on the first ride the bolt came loose again. Again, I could only use a hex key to tighten it.


I thought that maybe the threads the bolt goes into were stripped, but upon examination they're fine.
So my question is, what is causing the bolt to loosen and my crank arm to strip?
Is it improper torquing, my weight, or the fact that the bolt is tightened clockwise while I pedal counter clockwise?
Do I need a new BB set?

I called my bike shop and they're suggesting a steel crank arm, but I have a feeling that's a temporary solution.

edit: the bolt is also in perfect condition, the crank arm is starting to strip.