[mathking]

The advice to wait and see what the game is before you decide on a drive train is very sound. We did mecanum drive this year, and it drives well, but I would not have enjoyed trying to get this mecanum drive up some of the slick, narrow ramps last year.

That said, there are ways to cut down on the weight and cost. We made our gear boxes this year out of 1.25" x 4" aluminum tubing. Each box has two gears and a sprocket for the back wheel and two gears and a sprocket for the front wheel. This meant only two gear boxes and less weight. This year's drive train components were no more heavy than last year's 4WD. And the total cost was $375 for the wheels from AndyMark and about $220 for the gears, sprockets, shaft and tubing from McMaster. Not cheap but not prohibitively expensive either.

The most difficult thing we had to do was to balance the weight. When we first started driving, before the "arm" was done, we had to clamp a bunch of C-clamps to the frame to make it strafe straight. But we found that some prior planning made it fairly easy to distribute the weight properly. We have been satisfied with its performance in practice, but we'll see how it does in competition this weekend at Buckeye. Hopefully it will work well.

Side note: Since this was our first year using mecanum, we also developed a more traditional drive train as a back-up. We ended up not needing it, but it helped knowing there was a back-up system. This development also gave some of the new students valuable experience and a chance for some of our younger veterans to get some leadership experience.