18"x10" and 18"x10.5" Track Wheels Options?

BGTV8

I run ARP 75mm studs and for the OEM wheels, have machined the ends off the OEM lug nuts - took 45 minutes in the lathe to do all 20 nuts, and then ran a tap thru to make sure the thread was cleaned up.

I have also decided to go 9.5 wide on 18's for my square setup with 265/35R18 tyres (lots of choices: Bridgestone RE55S, R888, Advan A050, DZ03G plus the Pirelli Corsa R-spec - one of my race buddies here in Melbourne is the Pirelli motorsport distributor supplying the Australian GT Championships with slick race tyres so I can get them at a reasonable price - for Aus).

My reasons: I reckon there is such a thing as too much tyre and 295 front/305 rear comes into that category on a car with near OEM levels of torque (definitely not true for FI engine though). My race car works just fine on 290mm slicks and it has 280Kwatw (soon to be 340). Too much tyre causes drag and friction which wastes the limited torque I have with the standard VQ37 engine. If/when I put the fat VQ37 engine into the Z34 that might change, but that is another story and a ways off at that.

The other benefit with 9.5 square and "little" tyres is that I can run standard suspension arm angles (mostly) as the rolling dia of the 265/35 is only 610mml down from ~670 for OEM tyres), so I lower the CoG and ride height by ~30mm without changing suspension angles so camber gain in bump is not as extreme as it might be on a lowered car. It does imply harder springs to keep the car off the ground though - but not a big step up (12kg/mm).

Wheels are Subaru spec (+37 offset) TC105N and I have 25mm spacer for the rear and 15mm spacer for the front so I finish up with +22 at front and +12 at rear. Spacers all machined hub-centric to suit OEM hub and wheel centre bore. If I can get a bit more negative at the front, I can go +12 front and +0 at the rear with a bit of attention to the inner guards - but that will be the absolute limit