posted January 01, 2003 08:12 PM         

Look for the placard on your vehicle. The placard, among many things, tells the original tire size, the original wheel size, and the proper inflation pressure for that tire size. The placard is usually located on a doorpost or in the glove box.

A better choice might be a P245/75R15. The overall diameter is within 1%, meaning your speedometer will still read reasonably accurately.

The major drawback is the load carrying capacity, but you can compensate by using 33 psi, which would give you the same capacity.
Even if Nissan chose the inflation pressure more for ride reasons and the load carrying capacity of the smaller tire is more than adequate, the additional inflation is a good idea. You would get better fuel economy, better tire wear, better wet traction, better snow traction, better steering response, better tire durability, and only give up a bit of ride harshness.

"They" say you should check your tire pressures once a month. (In case you didn't know, tires leak very slowly.) Don't trust the guys at the shop to check your inflation. These guys are paid by the hour and this is one of the easiest things to shortcut. Besides, there are a lot of mechanics you don't know where to look for the proper inflation. No, it is not on the sidewall.

Buy yourself a tire gauge - a $5.00 pencil gauge works just fine, but I prefer the pistol grip digitals because they are remarkably accurate. The check takes all of 5 minutes and it is the cheapest safety check you can make.

Hope this helps.