Cage base plates and suspension brackets, how thick?

2000 lb car - need to fab cage foot plates and pick up points for lower front a-arms. Is 1/8" enough or go to 3/16"? Cage is a little overkill 1 5/8 x .120 (could have gone .095)

You should go based on the rollcage rules for whatever series you're going to be racing in (or thicker if you feel that's not sufficient). I used 1/8" on my last cage because I had relatively small footprint for the spreader plates and the front downtubes were on the floor (though tied in to the sills). Here are the requirements for a few organizations I know:

Chumpcar: 0.125" (floor mounted)
NASA: 0.080"
SCCA: 0.080" to 0.25"

Don't forget to check on the total footprint area required (or sometimes it's minimum length of any single side of the plate).

The rules are a little sketchy for vintage racers when it comes to roll bars - 1967 scca gcr, but encouraged to go with more modern standards. I see a bit of everything in the paddocks. I think I'm ok on the base plates with 24 sq inches & 1/8". Feel like the suspension mounts may need to be a little beefier with some grippy tires.

NHRA rule book calls for 1/8" thick plates. Sometimes I might use 3/16", but it's usually overkill. When cage work is involved, it's never a bad thing to go above and beyond the minimum.

2000# car? In some classes you can go 1.5X.095. Check the rule book and go as small as possible. Allows for tighter bends and more clearance for you.

1/8 will be plenty. Tied into a floor pan, 3/16 might actually be weaker, more liable to punch straight through the floor like a punch than deform with it as 1/8 or 0.80 would. Note how SCCA has an upper limit, that's why.

Kenny_McCormic wrote: 1/8 will be plenty. Tied into a floor pan, 3/16 might actually be weaker, more liable to punch straight through the floor like a punch than deform with it as 1/8 or 0.80 would. Note how SCCA has an upper limit, that's why.

this.