I have high expectations as to how sturdy my 3D printed motor mounts will need to be.  This was a task I originally had metal performing.

However, I think I have a good candidate here...

I printed a couple variations on the interface to the mountain board trucks, and then tested the winner by subjecting it to some substantial abuse.

The bottom one in yellow ABS is the latest iteration.  

My distance from the hub to the motor shaft was off by 0.5mm, my motor bolt pattern was off by 1mm, and the cover ended up being within 1mm of the chain.

So some destructive testing got to happen. :) 

The previous version in pink did this when I subjected it to mounting it and then standing on the motor.  

The little white line of discoloration on the side of the truck interface is what ABS does when it is under too much stress.  I made that area thicker and added another cross-member.

I never really liked printing with ABS before, but now that I have my settings for it dialed in I'm much happier with it.

Layer adhesion was always a problem for me before with this when printing ABS. Printing it hot, fast, with a hot bed, and in a warm enclosure has solved all of my previous issues.

I'm sure I could still design a part that would pull itself off of the bed, but just a little planning seems to have sorted that.

Four more parts to go.