1/2 ton VS. 3/4 ton tire size

spm4520 · July 24, 2020

Can anyone help explain why my '97 Chevy 1/2 ton 4x4 comes stock with 265/75/16s which are a 1" taller and a 1" wider than my '02 2500HD 8.1l 4x4 that has 245/75/16s?

I've always felt like the 3/4 ton sits like a 2wd truck when compared to other "stock" 4x4s on the road. Maybe I have the last one in existence that hasn't had the torsion keys turned up or a leveling kit put on?

Was a larger tire size ever an option for a stock 2500HD?

CamGTP · July 24, 2020

The spec tires for what the vehicle can do, so that's kinda why they are skinnier and they can handle more weight.

That 245/75 was the tire size all the way to 2007 in the classic body style. Most people would switch to a 265/70/16 for a better look. Or they would go 265/75/16 for a 1in larger tire. You'd go from a 30.5 to a 31.5in tire.

spm4520 · July 25, 2020

I appreciate the reply but your answer seems counterintuitive. A smaller, skinnier tire can carry more load? I believe that opposite to be true. Compare the tire size of an appliance dolly to passenger car to semi truck to mega dump trucks. The larger the tire, the more surface area it has to distribute the load and reduce the strain on the tire.

Edited July 25, 2020 by spm4520

MORSNO · July 25, 2020

3 hours ago, spm4520 said:

I appreciate the reply but your answer seems counterintuitive. A smaller, skinnier tire can carry more load? I believe that opposite to be true. Compare the tire size of an appliance dolly to passenger car to semi truck to mega dump trucks. The larger the tire, the more surface area it has to distribute the load and reduce the strain on the tire.

There is a limit to where larger is better, the larger wide tires are D load rated many times (60psi vs 80psi max), so make sure you look at the load rating not just the size. Many smaller tires have high load ratings, especially when comparing 16" and 17", 17's have almost all been de-rated in load capacity recently for some unknown reason.

newdude · July 27, 2020

On 7/25/2020 at 10:27 AM, spm4520 said:

I appreciate the reply but your answer seems counterintuitive. A smaller, skinnier tire can carry more load? I believe that opposite to be true. Compare the tire size of an appliance dolly to passenger car to semi truck to mega dump trucks. The larger the tire, the more surface area it has to distribute the load and reduce the strain on the tire.

Tire size is not always directly related to load rating of the tire. Load index is very important as well. You never want to go under the stock load index, especially when it comes to trucks. Has to be the same or higher. P metric vs LT (C/D/E load) makes a difference.

2001-2006 HD trucks ran LT245/75R16 tires. E load. The load index on them is 120, which is 3169lbs. So, each tire is rated to carry 3169lbs. The only other size GM used in the 2004-2006 (excluding dually) was on 3500. They used an LT265/75R16 E load but on a 16x7in wheel. The 245 trucks have a 16x6.5in wheel.

The 265/75R16 tires on your 97 1/2 ton are most likely a P load tire (unless you've put LT on it). The load index on a P265/75R16 can vary by manufacturer, but its between 114 and 116 so 2640-2806lbs. So P tires vs LT will make a big difference in the load capability of each tire.

Therefore, an LT245/75R16 E is a higher capacity tire than a P265/75R16.

On LT tires, yes, the load rating will increase with size, but you still have to watch. An LT265/75R16 E load would have a load index of 123 (3472lbs) and would have more load capacity than the LT245/75R16.

Edited July 27, 2020 by newdude