Roll Cage Question

[anthony1k]

The roll cage of my most recent aquisistion sits a bit too low for my taste. I would like to raise it by about 1/2 inch all around. I was thinking of cutting where the tubes meet the floor plates and welding extra steel plates. Does anyone see a problem with this plan? TIA

[joeg]

No problem with the theory. In practice, however, it could get interesting with the fit of the rear bracing tubes.

[TomL]

I've done something similar when I redid a cage, but it involved raising the whole thing two inches (I slid in two inch box tubing instead of a half inch plate). But it was a LOT of work - it required replacing rear tubes and redoing forward braces among other things. I can't imagine a situation where it would be worthwhile to do all that work for just a 1/2" taller cage.

[Flyinglizard]

Email me and I'll show you the solution. I have it in my book. " I'll send you a piece

[anthony1k]

Thank you all for the responses. I should have been more specific. Actually extensive reinforcement work is being done to the cage. So since I'm at it, I might as well try to raise it.

Flyinglizard you have mail.

[timo944]

Actually I have to disagree. This is a problem. First, what is the date of the logbook? If it is later than 1/1/2008, then the current rule 9.4.E.3.a. applies:
"Mounting plates welded to the structure of the car shall

not be less than .080 inches thick nor more than 0.25
inches thick. The maximum area of each mounting plate in
the American Sedan, Improved Touring, Showroom Stock,
Spec Miata, and Touring classes shall be 144 square
inches. Plates may be on multiple planes but shall not be

greater than 15 inches on any side."

If it is before that it's a bit challenging, because the GCR refers you to appendix I that has no specific rule for IT cars., so you may need to refer to Appendix I,

9.4.7. APPENDAGES

The following procedures are approved for modification to roll bars/cages
that do not meet the two (2) inch required minimum: The old main hoop
may be cut off near the chassis mounting and a new main hoop of equal
tube size or a section of equal tubing size may be added, and inner tube(s)
must be used to mate all sections together. All braces must be minimum
distance from top of hoop per Section 9.4. All welding for this modification
must be arc welded (min.). The inner tube(s) must be rosette welded

three (3) places near top and bottom, see figure 21.

I'd like to hear thoughts on this since I am in the exact same position as you are. So far, I have been happy to keep my head rested against the roll hoop while driving, even if the world is tilted a little to the left.