Racing Kart chassis-Steel vs Chromoly?

[rkcarguy]

I've been reading rules for sprint(road course)kart racing, and being a fabricator by trade, am looking at either buying or building my own kart chassis.
The rule set states minimum tube diameters and wall thickness which seem adequate for mild steel construction.(1dia x.078", 1-1/8dia x.060", 1-1/4dia x.060"). While chromoly is stronger and more rigid, there is no weight advantage as some think. The weight advantage comes from being able to use a thinner wall or smaller member chromoly in the place of a heavier steel one.
With chassis flex being a major player in the handling along with the live axle(getting that inside rear wheel to lift to minimize scrubbing in the corners) wouldn't chromoly be a waste of money faced with the member size rules above?

 

[devino246]

.060 is a little less than 1/16 in which seems a tad thin for mild steel, IMO. Keep in mind, chromolly needs to be TIG welded and heat treated, although being a fabricator, Im sure you already knew that.

 

[TorqueRanger]

I would use dom tubing because chromoly is a tubing that is harder to weld and requires more steps in order to be stronger otherwise dom is you best choice .. In order to keep chromoly stronger after welding you have to normalize the metal to keep the strength..

 

[rkcarguy]

Sorry I forgot to mention, the tube avail is a DOM type.
I'm looking at using either the 1x .083 or a 1-1/4 x .065".
I'm aware that if chromoly the frame would have to be normalized in an oven and that's a pain...not to mention the cost of the tube. I priced an 8' chunk at $48 when I can get enough DOM for 2 kart frames for the same money.
I think the 1-1/4 x .065 main rails and 1x.083 engine mount rails would be the hot ticket properly gusset'd.
Would probably tack everything with the tig and then load some
.023 wire in the Millermatic 250 for this work.