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I received my foot drives from JAG not too long ago and I finally got them installed and R2 is standing on his own wheels now. Here's a link to JAG's site about the drives. The Drives consist of an omni-ball back caster and a large grey rubber wheel for the front that is geared for a timing belt (included) that will attach to a geared hub that is keyed to fit a motor shaft. The caster and wheel are mounted to a heavy duty steel casing that fits into R2's feet. There is also a plate on the drive for attaching the motor which will sit outside the foot in the battery box. The picture below shows the assembled drive sitting next to an upside R2 foot.



In this picture I removed the front wheel and you can see how the drive basically rests inside the foot on the center u-channel that comes up inside the foot. There are 6 screws that hold the drive into place, so there are 6 holes that need to be drilled into the feet. The holes in the drive are threaded.



I started by making 3 small holes to get my centers, don't let the angle and shadows in the picture fool you, the holes are centered!



I then enlarged and countersunk the holes in the feet. You have to be careful and not drill too much with the countersink bit, the steel is thin and the hole will become too big quickly.



The drives came with round headed machine screws to install, they are the ones in the back. They were a bit "bumpy" for me so I got some undercut flat headed machine screws from McMaster and they were perfect. They are the ones in the front, much more flat.



Regular Flat headed screws wouldn't work because the tapered part of the screw is too long compared to the thickness of the steel. The undercut ones have a lower profile. This picture shows the difference.



The holes still need to be countersunk a little bit more to get them totally flush, I was really nervous about messing the holes up so I countersunk them a little too little. Eventually once they are flush the plan is just to glue down a thin piece of styrene over the screw heads to hide them and if down the line I really need to remove them it won't be a big deal to remove and re-do the styrene. You can also see the plate on the right that will connect to the motor.



Time to get the motors ready. These drives were setup to use NPC-2212 12v motors. I got them directly from NPC. The motors are double shafted, you need to cut off one of the shafts. I simply used a metal cutting disc on my dremel and it came right off, lots of sparks though, watch out. In this picture you can see an untouched motor and one with a shaft cutt off and a hub attached for the timing belt.



Here's a close up of the drive with the motor installed and the belt connected.



Here's the foot with the motor installed.



Here's R2 standing on his new wheels, Now i just need to get the motor controllers and the R/C stuff to get him rolling. All said, these were pretty easy to put in, did it in a day. Very strong, very durable drives. I highly recommend them!!