[RonnieS]

Originally Posted by Arpan

Those ratios are just about perfect.

Have you considered trying to make the Cims or shafts removable to facilitate easy gearbox removal?

Also, you may want more than just the two holes in the WCD block to mount the gearbox to the tube. Two more holes higher up on the gearbox would add a lot of strength.

The two lower bolts on the gear box should be able to go through the tubing used on drive rail. You would drill a clearance whole on the outer wall and the correct size on the interior wall.