What is everyone using as race tire sizes? Specifically in 18", because there are no good combos in the stock sizes. Any help would be great!

2003 BLK/BLK 6-spd Injen clear corners

 

For what, autocross? Track use?

I don't use them yet, but might eventually for autocross. For this type of application, it's okay to get a smaller diameter, and exceed the 3% recommendation. Why? Because you're not putting that many miles on the car in that condition. The smaller tires will weigh less, help acceleration a bit, though you'll be going slower than the speedo says and wind up using higher gears in places where you wouldn't with stock tires sizes.

For instance, my stock size is 215/55R17. Looking at the available race tire choices that fit a 17x7 rim, 225/45R17 would probably be what I would choose. It's about 5% smaller, fits a 7" wide rim, and the speedo would read 60 when I'm only going 57. I wouldn't use this size for daily driving, but for racing applications, it should work great.

For your application, pay attention to the width of your rims, and use a site like tirerack to view the specs for the various size tires you're looking at. Find something close to the profile you're using, and check to see how close it is with a tire size calculator.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

Thanks! Preferably auto x, but I would be equally interested in track use as well :-)

2003 BLK/BLK 6-spd Injen clear corners

 

Guess no one races their G...

2003 BLK/BLK 6-spd Injen clear corners

 

I use the Falken Azenis for autocross, but they don't make anything above 17". These are extremely popular as a non-R compound tire.

'03 AT Sedan | Silver/Willow | Sport | Premium | Aerokit w/Spoiler | Nav | Injen CAI | UR Pulley | Tein Flex w/EDFC | Stillen Rotors | Cusco Sways | TS ECU | Stillen Exhaust

 

I do road races rather than autocrosses.

I would highly recommend running 17" wheels for increased tire choices and reduced mass. Look no further than our own backyard for some economical OEM 17" 350Z/G-Coupe wheels. They only cost me $300 for the entire set with used tires!!! Life's far simpler when you have a dedicated set of track tires anyhow.

I'm currently running the Hoosier R3S03s 225/45-17 front and 245/40-17 rear. For autocross, you'd want to go with the softer A3S03. Many people also have a lot of success running Kuhmo V700 Victoracers as well for autocrosses.

Clint (THX723)