Need some advice lads.
For the street I have changed to Enkei forged 19" split spoke wheels, to fit over the StopTech 14.1" big brake kit. Michelin Pilot sport 245/35 F and 275/35 R. Everything ok there.

For the track I cannot use the stock Infiniti wheels, because even though they are 18", they do not fit over the Stop Techs. And they weigh too much anyway, at 24.5 pounds. So probably going to the approximately 18 pound Nismo wheels at 18", as they do fit over the Stop Techs and are pretty good value.

But the tires are a conundrum.

Stock tires are 225/45 and 245/45 respectively. That makes for a 25.8 inch front diameter and 26.8 inch rear diameter.

Track tires have very few size selection choices that will fit, and these seem to be the best alternatives: (Michelin Pilot Sport Cup) are 225/40/YR18 front and 265/35/YR18, and thus have diameter of 25.1 inch front and 25.2 inch rear. Pirelli P Zero Corsa are about the same at 25 front and 25.1 rear diameters for the same size tire. Hoosier R3S03 are sized a little differently, with a diameter of 25.3 inches front and rear, sizes being 245/40/ZR18 front and 275/35/ZR18 rear.

The obvious concerns are:
1) the stock set up is an inch taller in the rear than it is in the front, while the track set ups are all essentially the same height front and rear. What problem if any will that cause, especially with VDC.
2)the stock set up is about .7" taller in front, and 1.6" taller in the rear, than the track set up.

Variance to true readings on the speedometer are not important at all. But having VDC engage just as a result of speed would be nasty, though I can turn it off. Any other issues to be concerned about? Anybody else having this much brain cramp over finding a good tire and wheel combo for the track?

 

I'm running 245/40-18 Hoosier R3S03 all around on a set of stock Track package Rays wheels. Coupld of reasons I went with this:
- A 245 section Hoosier is pretty much gripper than 265 section anything else (assuming you have decent neg camber)
- Same size all around reduces the understeer built into the car (again camber dependent)
- I can fit all 4 wheels and tires in my car (I think it would be tough with anything wider than that)

Also to answer your question - if you are at the level where you can handle an R-compound (particularly a Hoosier) on the track, you shouldn't have VDC or TCS on - hence no problems with that.

I did wrestle with what tire/wheel to go with on the track but I'm quite happy with this (now that I know they fit inside the car).

Jason

 

I'd get 4 of the wider 18x9.5 NISMO wheels and use 265/35 all around... Michelin Pilot Sport Cups, Pirelli PZero Corsa or Kumho ECSTA V700 all come in that size.

Just my $0.02 worth...

PeteH