Would it make a difference if I lowerd my tire pressure? Every one says to but im not sure. Im running nitto 555R drag radials 275/40/17 at 42 or 43 psi. I had them put on brand new about 3 months ago. In my ss I have 3200 stall and 389 gears. I usually rev it up to 25 or 2600 rpm when leaving the line and cutting a 60' of 1.84. i seem to hook up every time. I might spin the tires 1 out of every 5 runs I make. But I really never feel it spin. I remeber once lowering my tire pressure b4 i did my mods and i spun spun spun. B4 I had lowered them i wasnt spining. So what do you guys think? Should I try lowering the pressure or keep it at what its at and am I launching at the right rpm?

 

43 PSI is a little bitty too high. You are causing the tires to be deformed andcausing the center of the tireto do most of thework. You don't want car tires to look like motorcycle tires bulging out in the center, motorcycles have other needs. Bring the pressure down to the recommended 30 to 35 PSI. Your car will ride and handle much better, better traction, and the tires will wear evenly instead of just the center strip.

 

what should the front tires be at?

 

Front and rear should be the same, because that is how the factory tuned the suspension. There should be a sticker somewhere on the door jamb, but the factory spec is 30 PSI front & rear, cold. Cold means that the car was stopped in the shade for around 4 - 6 hours, and driven less than 3 miles before the pressure was checked. Don't go by what is printed on the sidewall of the tire, that is the maximum pressure that the tire can stand without causing damage to the tire. Tire pressure will normally increase ad the tires warm up, do not lower the pressure on a warm tire as the tire can overheat and blow out.

 

Ok so ill lower it down to 30 or psi. But what about when racing shouldI lower it to 20 or 15 or just leave it about 32 psi?

 

With regular radial tires lowering pressure below normal doesn't improve forward traction that much, with drag radials it will help, up to a point. Street handling will be impaired if the pressure is below or above spec. There should be asticker in the driver's doorgiving two air pressure requirements, such as 30 PSI normal driving, and 32 PSI for high speed driving. In any event don't go below 20 PSI as the tires may slip on the rim & loose air and the car may get out of control.

 

Street tires tend to cup when the pressure is too low as well. So when you get down to 15psi, you're getting more contact patch forward and back, but you're losing traction in the center of the tire, along with creating more rolling resistance, slowing you down after you have caught traction and reducing your trap speeds.

Bottom line, run them at 25-30psi, and you'll do about as well as the tires will do.