[JesseK]

We direct drove our Mecanum drive last year on cantilevered TB-Nanos (hex shafts). We went over the bump once per match on average, and rarely had a 'soft landing' on the other side. Not only did we do 2 competitions (1 regular, 1 offseason), we also had about 15 hours of little kids driving the robot around at the USSEF. Everything was fine for the most part (dirt kept getting in the gearboxes from the SEF floor).

We had a very slight issue with our Toughbox Nanos that we discovered during the build season. One of the bearings on the output shaft could wiggle as if the gear wasn't spaced properly. We added custom-shaved washers to them, and they worked beautifully after that. I'll note that these were the first iterations of the TB-Nanos, and from what I can tell AM fixed that issue in the iteration after.

I'll also second Chris's statement about keeping the wheels as close to the gearbox as possible. Also use 2 hubs per wheel if you can since the wheel is slightly wider than the output shaft's length.