[Ben Wolsieffer]

On our 2010, 2011 and 2012 robots we used the original 8in AndyMark mecanums (w/o the side outer rollers). These worked well, but after a couple of seasons we had lots of bent axles (which can be easily replaced) and the rollers were pretty worn.

This year we decided to upgrade to the new 8in AndyMark wheels which are a lot beefier than our old ones. They can support up to 500 lbs per wheel, compared to 180 with the old ones. This helps prevent axle bending when if the robot ever slams into the ground (we accidentally drove our robot off the cart once and the wheels were fine). The main functional difference between the original AndyMark wheels and the new ones is the addition of a set of roller outside of the wheel plates. These greatly reduce the vibration of the robot as it rolls from roller to roller.

My main complaint with the AndyMark wheels is that they are difficult to assemble. The roller bolts that were provided were just barely long enough to reach the nylon part of the nut on the other side and we had to get them just right to prevent the nuts from falling off or the rollers from binding. We had problems with rollers binding when the wheels were brand new, but after a lot of practice and a couple competitions they now roll perfectly and we haven't had any problems with them at all.

Lastly, I would not recommend wheels that use plastic to attach the rollers simply because I have seen snapped off rollers too many times to feel comfortable with them.