Regulation for roll cage tubing diameter?

#1

It looks like the CCR rules changed after the last post I could find regarding tubing diameter. Since the race weight of the E30 is 2700# and driver plus fuel is on the order of 250# I’m assuming the cage tubing falls into this section of CCR 15.6.18:

1501 - 2500 lbs.
1.500” x 0.095” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
1.500” x 0.120” ERW* (No issuance of log books for cars with ERW cages 04/30/03)
*Note- Specifications listed for reference for inspection of grandfathered vehicles.

Is this a valid interpretation or do I need the 1.750" x 0.095" tubing?

#2

Yes, SE30’s fall under 1501-2500 lb limits. My cage is built with 1.500” x 0.095”.

Allan

#3

“For the purposes of determining roll bar tubing sizes, vehicle weight is as raced, but
without fuel and driver.”

This is what is in the CCR. If a driver is under 200 lbs then you must use the 2501-3000 spec. If you build a car to the 1501-2500 you may be limiting the potential market if you ever sell.

I think we need to have a rule stating we must use the 2501-3000 spec to make sure everyone is covered and the new cars are similar to the older cars.

#4

“…vehicle weight is as raced, but
without fuel and driver.”

I’m about 150 and it seems that to make weight and avoid fuel delivery problems a lot of folks are starting with full fuel tanks. This being my first E30 I don’t have a very good feel for fuel consumption on the track but I’m guessing folks who start full end with around 1/2 to 2/3s of a tank. At 6# a gallon that’s roughly 50#. So 2700 minus 150 minus 50… Oops, no margin. So 1.75 it is. Thanks for correcting me Michael.

#5

You are correct. The rule does not care if you use fuel as ballast. Fuel is fuel. Theoretically, you could coast across the start/finish line and get pushed to the impound if need be.