im planning on building my own roll cage for track days and the odd race. the thing is i cant find any specifications on what tube size it needs to be and if it needs testing. i was thinking of using 48mm tubing with a wall thickness of 3mm for the main hoop and then 40mm tubing with a wall thickness of 2.5mm for the bracing. i also dont want door braces as it will be a bugger to get out of the car. but do i need them for trackdays. also where would i bolt/weld the frame to the floor and do i need inspection holes aswell? thanks:blink: