Hi Tomas
Oh I'm a little happy to hear this is not your personal problem, but as it is your customer, it still your problem
NEVER have I seen anybody
break/
snap the thread on the hub casing!! Lol that is why I said 'he must have strong legs'
As it has happened twice, I assume your customer probably has something wrong in the chain drive. This is only going by the time I spend on forums and 'ebike' problems I've researched. This one was surprising to see
It could be many things, but I do not think at the cause of the motor. I could even be safe to say the first one you sold 'never' failed, as it was probably never designed for the stress it took.
Some things that come to mind:
1- Maybe the rear too tight, with little room causing the freewheel to rub against the frame. Maybe this caused it to snap if it got stuck.
2- Somehow the rider is using an
extremely tight chain causing much stress(damage) on the freewheel
3- The chain alignment could be off center, making the freewheel want to pull to one side; maybe causing it to break
4- The freewheel screwed on too tight using a tool when installed
5- The freewheel not screwed on enough, or too many washers put in front of freewheel
Those are just some thoughts..
Since it happened twice, I doubt it's a defect in the product. It appears very hard for someone to break that !
Hopefully you do not hear about the problem again
