Proper Tire Pressure

[bad monkey]

This is my first time started a thread, so in true message board fashion... Let the Flaming Begin!!!

I recently bought the Sumitomo HR200 summer tires. I filled them up when I got home back to the 42/40 I ran my Incrapities at. I now notice that they look underinflated. I went from the stock 185/65 to 195/60. I love them. They no longer "chirp" at intersections, or squeal turning sharp corners at speed.

I remember from my racing video games that you could adjust both camber and pressure by comparing the inner, outer, and middle tire temperatures. Lower temp in the middle, too little air, higher temp, too much air. Of course, camber by comparing the outside temeratures aginst each other is not part of this threads perview.

If anyone has a better idea let me know, but I want to take a laser-infrared thermometer and measure the temps and see if a) I can measure a difference, and b) if my readings will be consistant and accurate enough to adjust the pressure to an optimum, ideal for my car, my tires, and my driving.

[tochatihu]

I am not familiar with the technique you mention. What I do is use a $20 digital caliper/depth gauge to measure tread depths, with quite a bit of replication. Do it again 3 or 4 thousand miles later and compare the results. If you have even wear across the width of the tire tread, than you are at the best tire pressure (or so says I). If the edges are wearing faster than the center, try a few psi more the next time around.

Obviously maxing out the payload capacity of the car will require a bit higher inflation. Exceeding the max cold psi specification on the tire sidewall is not recommended. You will probably end up with a few psi higher in the fronts than rears; this is linked to the unequal F/R weight distribution of the car. Also to slip angles while cornering but I do not understand that well enough to attempt an explanation.