tire questions

elk_hunter · November 3, 2003

Just about to get new tires for my truck 99 GMC sierra ext cab. Do light hauing, and towing(might get a truck camper or pop-up before next sumemr)

I have it down to two brands.

First one

P245/75/16

Temp rating A

Traction rating B

Speed rating S (112)

load rating 109 (2271 lbs)

Second tire

LT245/75/16

Temp rating C

Traction rating A

Speed rating Q(100)

load rating 116(2756)

as you see the first tire has betting speed,heat rating, but the second has traction/load ratting better.

I usuallly drive in city, but when on highway i'm running about 75-80.

Thanks for any advice you can give!!!

Thanks!!!

Shotgun · November 3, 2003

LT is always a better truck tire in my opinion.The LT's have a sturdier sidewall and handle more weight.

elk_hunter · November 3, 2003

yea that is how i though too,

but that temp rating of only C, and the speed of only 100mph is what i'm worried about

Ben · November 3, 2003

Not comparing apples to apples.

P rated is Passenger rated tire and must be DE-RATED mine 9% when used in LT applications (hauling/towing heavy). Why similar sized will have the LT weigh more and cost more. There's more stuff going into it both in designe/engineering/manufacturing processes/etc.

LT rated is light truck and has tougher sidewalls both in stiffness to manage that "push" from towing and hauling heavy and to carry weight.

Here's some hot links to tire info sites and some that list the 9% DE-RATE (note many believe, so have saved the links to show folks).

...best tire info site found to date. Easy to read and understand. Note the 9% DE-RATE of P rated tires.

...Firestone 9% de-rate

FourWheeler mag article

Ben · November 3, 2003

Forgot, if you use your truck more as a "car" then P rated is just fine.

Your "speed" rating keys to this, as LT tires are only speed rated to 100mph and why the computers have speed limit of 100mph.

Note that only 1/2 ton should even consider P rated tires unless the load rating *AFTER* the 9% de-rate still has enough weight carrying. Even then the sidewalls will be too soft to really do a decent job. Why dually better haul/tow vehicle...8 sidewalls vs 4 sidewalls and all LT rated to boot.

[edit]....also forgot that those with the "HD" model should know that it's not as badged...it's really next size up. A 1500HD is really a 3/4 ton and a 2500HD is really a 1 ton...check the GVWR to confirm. Badging today is bogus marketing and really should be looking at the GVWR to really know what it is

Shaners · November 3, 2003

I would go with the LT tire. It may ride a little stiffer than the other choice, but in the long run you will have a tire on your truck that is more capable for what your truck was designed for.

It's always a good idea to have a little too much rather than not quite enough.

MattDewalt · November 3, 2003

Traction is more of an important consideration then temperature. Most of us will never put enough heat into a tire to have temperature become a factor. Traction on the other hand is misunderstood by a lot of people. It's not the tires ability to get traction when driving along. It's the tires ability to brake when it is wet out. After a summer like this and switching from B traction to A traction tires, there was a noticeable difference to me. Wet braking is not only rain, but also snow/slush. I'd much rather have a tire that stops well in poor conditions. As far as the "P" rated vs. "LT" rated, it depends on how your truck is used. I have a 1/2 ton that tows my 4 wheeler about 10 times a year for a trip of 2 hours. Other than that, it's always unloaded. I went with "P" tires because I use it more as a car for back and forth to work. I also never exceed the GAWR (gross axle weight rating) of my axles. The "P" rated tires have enough weight rating for how I use my truck. If I were towing heavier loads and doing it more frequently, I would go with the "LT" tires.