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What is the Difference Between Load Range C and D ST175/80D13 Trailer Tires  

Updated 03/08/2026 | Published 11/04/2011

Question:

My trailer tires are branded ST175/80D13 Load Range C. These tires are also ST175/80D13 but Load Range D. My question is how do they differ, size wise? Sould they still fit my trailer without tire rub?

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Expert Reply:

The difference between an load range C and load range D tire in the same size is the capacity and psi rating. The two tires will still have the same dimensions and fit on the same wheel. The D rated tire has a higher capacity.

For a ST175/80D13 like # AM1ST77, the capacity is 1,610 pounds at 65 psi. For a C load range in the same size, like # AM1ST76 , the capacity is 1,360 pounds at 50 psi. Adding the D load range tires of the same size will fit your trailer, but they will not allow you to carry more weight even if they are rated higher. You will still need to go by the axle capacity.

Always make sure that you inflate a trailer tire to the maximum psi rating as indicated on the tire for the best performance and longest life. I have included a link to our FAQ article on trailer tires for you.

expert reply by:
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Michael H
Brian P. profile picture

Brian P.

7/2/2020

You should also explain that to get the maximum value from a trailer, the axle rating and tires should be compatible. For example, if you have a single axle trailer and that axle is rated at 4k lbs, each tire should have a max load rating of 2k lbs, thus the combined tires equal the rating of the axle. Do not put tires on a trailer with a lower rating than the axle and still think you can haul the amount of weight the axle is rated for.

Chris R. profile picture
Etrailer Expert

Chris R.

7/7/2020

Absolutely correct.
Lowell N. profile picture

Lowell N.

2/16/2021

@BrianP do you have trailer tires 295/75/15 ,if so price and how to buy
Jon G. profile picture

Jon G.

2/16/2021

The closest we have is 235/75-15 which you can find on the linked page.
See All (5) Replies to Brian P. ∨
Ken W. profile picture

Ken W.

11/11/2021

I have a single axle jetski trailer with 175/80D13 tires. How do I determine the axel rating?

Les D. profile picture

Les D.

11/15/2021

@KenW There is usually a sticker on the axle. You could also refer to the trailer's GVWR.
Rick profile picture

Rick

3/8/2026

Will the D rated tire last longer than the C rated tire if compared on the same trailer and load weight ?

Jerred H. profile picture
Etrailer Expert

Jerred H.

3/8/2026

@Rick It sure will! The Loadstar ST175/80D13 Bias Trailer Tire - Load Range D item # AM1ST77 will last longer because it has a higher weight capacity, stiffer sidewalls, and runs cooler. The increased ply rating also has better resistance to heat buildup and damage from road hazards.
Rick profile picture

Rick

3/8/2026

@JerredH I would go with the radial. I’m guessing it would work the same way ?
Jerred H. profile picture
Etrailer Expert

Jerred H.

3/8/2026

@Rick Yes, it will!

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