As with all products, it's how you implement the product that matters.
We used 1"x1"x.04" for our frame in 2014, except for the two main rails running down the center of our chassis that was bearing the load of the catapult tubing. No issues, no bending, we could have parked a bus on it. The trick wasn't the tubing but how it was designed into the final product. We did utilize a single gusset plate for the entire chassis instead of using many Vex gussets which improved rigidity.
We also used 1"x2" Vex VersaFrame for our catapult arm assembly.
With this we used the Vex gussets and found that the aluminum rivets were loosening up. We switched from aluminum to steel rivets on the gussets where the most load was being applied and they stayed nice and tight for the rest of the season.
Here's a link to a picture of the .04" wall chassis we used this year.
http://www.chiefdelphi.com/forums/sh...=pwnage+swerve