[JesseK]

The major flaw I saw at champ's with design that Alex posted is with the side rails -- the ones that are supposed to back the bumpers. 973, 254, 968, and 1868 all used the same exact drive train with minor differences. Their bumper-backing side rails were made out of 1/2" box tubing.

On 3 out of the 4, that 1/2" box tubing was warped or bowed inward by 1/8" to 1/4" -- somewhat negating its effectiveness and being technically illegal to the most pedantic of bumper rule interpretations. To be honest, 99% of 2-level welded frames I saw are in violation, even ours. It's simply too difficult to get that thing 100% straight if it's not perfectly flat on a welding table

1" box tubing could possibly make the 2x1" vertical frame members torsion/warp rather than simply the side rail, which would then stress the side rails that hold the wheels. I'd consult with a welder before giving that concern any weight though. Perhaps Cory will chime in if he sees this.

It's easy to prevent warping during welding on a 2D frame (just the 2x1 rails). Yet things can get very tricky when moving to a level that isn't clamped directly to the welding table. It's one of the many reasons why WCD has been a very successful drive train for so many years -- its function:simplicity "ratio" is unsurpassed, thus it mitigates many of the issues that more complex frames have. Compliance with bumper rules in recent years has been the root cause of the extra necessary complexity of side rails.