As posted by Jesse: http://www.tirerack.com/tires/tiretech/general/align.htm
This is a good article which will give you a better understanding of terms surrounding tires, alignment and wheels.
This is a good site I found a while ago to calculate the different aspects of different tire sizes when mixing tire sizes and profiles.
This site states the recommended air pressure levels for both front and rear tires for all Nissan’s.
http://www.drivegreen.com/PressureValue/Nissan_Datsun.shtml
Don’t neglect your tire pressure, is surprising how much of a difference a few PSI can make. Remember to get your readings when the tires are cold also (re: hot air expands yielding false readings).
If you’re gonna race on a track or drive at fast(er) speeds, you should run a higher pressure than stock. Sounds obvious but a lot of people don’t know it.
Could you explain please why you would want to use a higher pressure.
Tire pressure on the track is one thing that a lot of people argue about. There is no optimal pressure. It all depends on the tire, the driver, and the car. Now let me explain how all this is related.
Why run a higher pressure than Nissan’s recommendations for the 240SX on stock tires? Basically, it comes down to this. The stock tire pressure recomendations are made by Nissan to provide all-around good performance, ride, and comfort. It’s not specified for the track. The stock tires have a fairly high sidewall, which also makes them less stable at their limits of adhesion due to the sideplay that occurs in the sidewall during heavy cornering. Raising the cold pressure by a few psi creates more pressure within the tire and resistance to the sidewall play, which usually provides improvement in steering response and cornering ability.
Now here’s the part where the driver comes into play. What is optimal for one, is discomforting for others. You should run whatever works best for you, makes you feel safer, and of course get you the quickest laps while doing the previous two.
When you get into performance and low-profile tires, it’s another story.
i do agree, when i have the tire pressure that nissan suggest my car feels soft around the corrners but less harsh of a ride. when i run at the 41psi that i have currently i have a much greater steering responce and the car does old the corrners better. but now watch out. you still also have to judge the amount of pressure also on the tire. a 35 in one can feel harder then a 43 in another