I had a cage built for my car this year. My intent was to have a cage that complied with ITS, SpecE30, and KP classes (SCCA, NASA, BMWCCA, respectively). Unfortunately (or fortunately, as it may be), I ended up with a cage that is not legal for ITS according to the 2008 GCR.

Until 2008, 1.5 x .120 mild steel was acceptable for a car with a class weight of 2750 lb. That's what I have. Now, the minimum is 1.750 x .090 (GCR 9.4.F)

I don't have a huge problem with this; it's my job to check the rules and tell the builder what I need. I'll run E Production if I have to (the car would not be competitive in ITS anyway).

But I'm curious. Does anyone know why the cage rules were changed for 2008?