Print N and P Wheel Hub's as many as you need.
Print R (roller) - will print 6 Rollers, each takes eleven rollers.
Trim any Ozebane and maybe sand the "top" side of the roller to make it flat and smooth.
Remove any Ozebane and other dimpled in the wheelspaces.
Fixing rollers in HUB:
Use small pcs (approx 10 mm) of 3 MM filament as axels.
Remenber to add rubber rim (O-rings, like farnell 185-2406)
Naturally the size of the O-ring is importan - you can get O-rings many places.
The axels are glued into the sockets with some ABS dissolved in Acetone
--- my nxt mindstorm has only 3 motors, and you need 4 to drive the wheels in any direction....
--- Can somebody please make a Gearbox for 4 mechanum wheels.
there are 6 gearstick postions: