Posted by Ben on April 09, 02 at 21:21:50:
In Reply to: Tires posted by JimBob on April 09, 02 at 12:19:38:
Check out the below web links (hot links good general info for both tire and wheel terminology/technology) and #1 Son's web pages for general Suburban/truck info).
http://server3002.freeyellow.com/subtopics/subtopics.htm ....General Suburban/Truck info site
http://server3002.freeyellow.com/subtopics/Tires-Wheels.htm ....Tire info site.
First understand that a Suburban is a "TRUCK" based vehicle with passenger car attributes. The SUV craze has the manufacturers adding more and more "car" like stuff all the time. If you use the Suburban as a "car", then "car" tires will do...maybe. If you use your Suburban like a truck, then "truck" tires are a must.
"LT" tires are designed for trucks. LT stands for "light truck" tire. Ratings are by letter designation, which used to correlate to the number of side wall plys. Nowa days, most LT tires all have two or three sidewall plys no matter what the letter designation is. They make up for it with stronger threads in the ply webing and size of the plys.
"P" rated tires are for SUV's used like a "car" and is designed more for "ride quality" than load carrying capacity. Load rating is numeric and referenced to corresponding KG/LB number. NOTE that when used to haul heavy loads or tow, there is a "derating" of that load number. Have seen published percentage number and think it was 9% derating.
The sidewall pressure is different between "P" rated and "LT" rated tires. "P" rated have seen up to 50psi max and "LT" rated have seen up to 90psi max. Factor in the derating and you can see that one is only station wagon type of usage vs truck type of usage.
Confusing since they both now come in truck sizes and truck treads. BUT there is a difference. Read up at the listed web sites and the various tire manufactur's sites.
Final note is that with a Suburban you can get into a lot of trouble with the wrong type of tire. Consider this: a 1500 Suburban can carry up to 9 people, their luggage and stuff on the roof rack. That means about 150lbs x 9 = 1350 lbs PLUS 50lb luggage x 9 = 450lb + 1350lb = 1800lbs. That can push the load on the tires over their limit, whereas a passenger car can't even put that much volume into it, let alone the poundage.