[ice.berg]

Couple things I can think of while looking at the design. Our team has done a jump drive/octo drive the past 2 years. Last year was all 4 corners had traction that actuated. And in 2012 we had a mechanum system with a 3rd set of wheels in the center with traction to actuate up and down for the bridge.

-We have found that the mech should be the natural position, then actuate the traction down from. In a sense the mech. is static and then the traction moves up and down.

- We used the same axel that the mech. rotated on to also rotate our traction wheel around.

-In between the two side plates I would recommend some kind of bracing or reinforcement. In a side collision I could see this flexing quite a bit.

-Be very careful with your Vex mech. wheels. For ultimate ascent they were fine through 3 rigorous events but they didn't last too long after that. Spares are a must.

-Our team prefers hex shaft over keyed. This is for 2 reasons, cant loose a hex as opposed to the key stock in the shaft. And hex has better engagement and less slop from what we have experienced. Downside to hex is the bearings can be touchy on tolerances, quality, and availability

But like all things in FIRST, there is no right way to do one thing and you can always improve on your design. So far you have a solid base it seems, and with some tweaking you should have a real nice system. I will try to snag some pictures of the systems if I have a chance to give you a better idea.