pic: Unobtainium 6wd - Cantilevered, Dead-Axle, Slot-Tensioned Drivetrain

[MrForbes]

Originally Posted by Mr. Lim

Did your wheel bearings rest on the threads of your threaded rod? If so, any concerns with this? Excessive play? Still worth the trade-off IMO, but curious nonetheless.

It's not a tight fit, there's a bit of slop, but it's only a few thousandths of an inch. And the reduced load bearing area of the threaded rod vs a solid shoulder bolt means that after decades of use, it might wear the threads enough that you'd want to think about replacing the axles. It's really not an issue at all. I've worked on enough old cars to have a pretty good feel for how long something like this will last.

Did you have frame flex issues at competition weight? Did you have to add more support to your C-channel side rails to prevent them from twisting, resulting in negative camber?

The frame is surprisingly stout for how little there is to it. The 1/16" aluminum bellypan and top corner gussets really make a strong structure when combined with the channel. Did I mention it's light? Notice that there really is no material where it doesn't need to be.

Was that a typo, or was your fibreglass C-channel really only 1/8" thick?

Yeah, only 1/8" thick, that's plenty strong. As far as weight, the fiberglass has roughly half the density of aluminum.

Again, this robot was designed for a specific game, and worked well for that game. The 2009 robot we made of wood was even more unconventional, and also worked very well for the game it had to play. The steel robot we made the following year didn't work as well, it had cantilevered axles, but because of the bumps it had to traverse, the axles bent significantly during the competitions.