Well after some research I find some those broken crankarm reports are very limited and confined to extreme abuse/use. I slo found standard offset crank arms fairly easy to find. Much adieu about nothing I think. That being said this old guy on a flat foot is unlikely to break one.
Good point Ann. There have been reports of problems with exactly the same back story. Stupid at the cranks from loose bolts and crass threaded pedals by home installs. Any alloy coteries crank can have the same problem. I've noticed many OEM's are using blur loctite. It make for a harder removal but can be a big problem solver. I think new mechanic and beginners might even consider a torque wrench and loctite. I've started using their green as it's a penetrant to be used after the install. But it's best used where the bolt or nut it positioned up so it can flow down. It doesn't flow sideways very well but still provides some grip.We saw more failures of pedals which customers often mislabeled as a 'crank arm' failure. It can also be an oversight of the shop or owner about checking tightness of crank arm bolts periodically. I agree with @LouisQ about Chinese steel manufacturing plants. A good many of those are newer, better quality production of steel than plants here in the US.
WOW, I have the latest iteration of apple operating systems. Apparently the "spiel chicker" is far more aggressive than previous versions. Instead of missing a letter, which typically accounts for most of my spelling errors, I'm getting completely new words. WOW!! I promise to look before hitting post from now on!Good point Ann. There have been reports of problems with exactly the same back story. Stupid Stripping at the cranks from loose bolts and crass cross threaded pedals by home installs. Any alloy coteries cotterless crank can have the same problem. I've noticed many OEM's are using blur blue loctite. It makes for a harder removal but can be a big problem solver. I think new mechanics and beginners might even consider a torque wrench and loctite. I've started using their green as it's a penetrant to be used after the install. But it's best used where the bolt or nut is positioned up so it can flow down. It doesn't flow sideways very well but still provides some grip.
The kit is not nor has ever been represented as a good choice for a jumper. There are motors, drives, and cranks that can take the abuse. Some simple searches would have revealed that. Look I'm not being, or meaning to be rude, but the kit just isn't built for the kind of use you're complaining it won't take. I knew that before I bought it. As to Chinese metallurgy that's a pretty broad statement. It's all a matter of the standards set by the company contracting services. I learned during my scooter years there are great reliable tough scooters that stand up to hard use. And there are shady seedy pieces of crap. It's up to the buyer to exercise due diligence. But your report of failed crank arms is greatly exaggerated. For every failure there are hundreds of successes. Buyers seldom post on the internets to report how great their units run. I've dealt with dozens of users and read nearly every thread and poste on ES and every other English speaking forum on the internet regarding the BBS0x. You are exaggerating the problem. It's just that simple. If you want a unit that will take the kind of ABUSE that jumping will dish out, I can make a recommendation. However you will find, on this particular forum there aren't a lot of users who give a hoot how the BBS0x will perform in a jump.