I asked the same and the told me this is the minimum number for BMW,PORSCHE,FERRARI,and general race cars for the track,I think 75 is a bit low and there is no harm to have them at 90
And you know this how? I guess the engineering knowledge at BMW, Porsche and Ferrari is nothing compared to the morons at the track.
It has never been insufficient for these cars in any use. The determining factors that go into wheel bolt torque do not include how fast you are going.
Over torquing is not without risks. Personally I'm not too excited about those inspectors, especially since they are probably responsible for inspecting other aspects for track safety with obviously many different makes and they have either this level of knowledge, don't care or possibly both at the same time.
A blanket statement by inspectors at a track re lug nut/bolt tightening for a street car on a track day doesn't consider the type/grade of the fitting, the material of which the wheel is made, the size of the fitting OR whether the fitting is to be lubricated or not. These items can vary widely from vehicle to vehicle per manufacturer specs. I have seen factory specs that call for as low as 50 lb/ft and as much as 145 lb ft on the wheel lugs. 90lbft torque might break/strip a 50 spec and 90 wouldn't be properly tight for 145 spec... On a RACE CAR, in whatever class, a "fixed" torque setting is reasonable because there are usually standard materials/specs decreed for all that but for a street car taken for a track day, it's not reasonable.
