[EricH]

Originally Posted by topgun

How did you attach the wheels to the drivetrain? A picture would help.

Offhand, I'd go with the wheels sliding onto the hex shafts (from left, the 1st, 5th, and 9th gears) and being held on by a washer attached to the end of the shaft by a screw into the end (note the tapped holes in the hex shafts).