Originally Posted by klapool
My son (13) and I got our 2 new China Girls on Friday.
We tore into the project yesterday. After futzing around with his bike we went to Wally World and picked up a cranbrook for him.
So while we were fitting the sprocket to the rim, following the directions in the box and on the DVD, we noticed that there is a grinding in the bearing on the axle. Not Good....
Also as we were tightening down the sprocket we noticed the sprocket start to deviate in shape.
The instructions say to tighten it down but now I see there must be a certain torque limit to the tightening.
What should I do with the bearings in the axle??? What should I do with the sprocket?
I think this is what you are looking for.
Motorized bicycle drive gear mod - YouTube
Although I don't like it, some have cut/ground the bearing cap lip off. All this has NOTHING to do with the bearing itself..I'm sure you just misunderstood the "DETAILED"....yea right" instructions.
And this might help.
As far as bolts to nuts the max torque is 92 inch pounds. I have found that the rag bolts and nuts are a Metric 8.8 grade..(look on the head of the bolt) but all other fasteners are junk Metric 3 (50 inch pounds).
I'm in need of the rag joint nuts (only), for a item that I make. I will send you 9 locking Grade 8.8 nuts for your stock nuts. Replace them and then send me yours.
Since you mentioned Cranbrook, make sure that the engine is mounted properly..if not I'd just about bet broken studs or mounts are in the near future.
JFYI The laws might require a minimum age of 15 to ride these bikes.