[sanddrag]

We did a 6WD WCD with 8" Pneumatic tires on custom hubs, Vex Pro 2-CIM ball-shifters, and Vex Pro 15mm belts. The ball-shifters performed flawlessly other than some wear on the 3rd stage pinion gear. I wasn't perfectly happy with the belts. We calculated, designed, and manufactured for perfect center to center distance and they were very loose, and needed significant tensioning. After tensioning, they still ratcheted quite a bit when going from forward to reverse, but we never broke, threw, or wore out one. Also, the robot drove very smooth and quiet with them, which I cannot necessarily say about chains.

We used thunderhex shaft and bearings, which both worked great, except for the thunderhex shaft needing some sanding down. We also made copious use of the Vex molded plastic hex spacers, which are perhaps one of my favorite products they offer entirely.

We used West Coast Products bearing blocks, which really can't be beat for the price. We could easily make ones, but we were not just buying bearing blocks, we were buying time. One thing about these bearing blocks that absolutely drives me nuts is that when used on a 1" wide tube, there is no screw that fits it perfect. The overall width when assembled is something like 1 5/16. As a result, you have to go with 1 3/8 screws, which stick out 1/16. Either the 3/16 thick block should be redesigned to 1/8 or the 1/8 thick block should be redesigned to be 3/16 thick. You just cannot easily get 1 5/16 flat head cap screws. It's an odd design.