Wheel fell off during a ride

Luckily I wasn't going fast or this could have really sucked. Bearing failed on the drive wheel and the wheel fell off...nut still attached.. Anyway, we think we know the story of what happened.

What happened.

• The mount will not fully tighten...and wiggles a bit no matter how hard you crank down on the nut.
• Mount at some point made contact with the rear sprocket and made aluminum shavings.
• Shavings get in the bearings.
• Bearing fails
• Wheel falls off

Some pictures of the carnage.

Bearing toast.

This is where the rear sprocket was making contact with the mount. You can see where it's been worn down (silver ring). You might notice the wear pattern is a bit non-symmetrical...more wear on one side of the sprocket. This shows how the sprocket is not perfectly aligned to the wheel. I've made a previous log about this problem, but this is best I can align the them.

Lots of aluminum powder came out of the wheel hub when I took off the sprocket.

After about 5-8 miles, the heat shrink is pretty much toast from the slight wiggle in the mount-trunk union. Just can't get a perfect, permanent fit. Heat shrink probably isn't the best material for this...sucks actually.

Conclusions:

So this is our first "test" board. We plan on making 3...one for me and 2 more for the boys. It's been a really great learning process and we've had lots of fun. What's next?

• This motor mount just can't be made to have a permanent fit...requires constant adjustment after each ride. Doesn't matter what material you use to improve the gap. Tried everything including aluminum shims.
• Rear wheel sprocket setup is OK...so far hasn't needed much adjustment after getting it fit
• We'll be trying the Enertion setup next time.