How to Select Trailer Tires with Correct Load Range Rating for Trailer Gross Weight

Question

Question:

Hi, I understand that trailer tires have designated load ranges. What I do fully understand it exactly what that load range means. For example if a trailer tire has a 1300 lb load range capacity, does that mean if you had a trailer with 4 tires two axles the maximum weight of the trailer should not exceed 5200 lbs? 4 x 1300= 5200? In other words, If I had a trailer that has a gross loaded weight of 4000 lbs, each of the 4 tires would have to be load rated for at least 1000 lbs or more? Thank you.

asked by: James L

0

Expert Reply:

Your math is correct in your trailer weight load example. If a fully-loaded tandem axle trailer weighs 4000-lbs then each of the 4 tires will bear 1/4th of that load, or 1000-lbs. In this case a tire rated for 1300-lbs would provide a good safety margin. A tire's rated Load Range means the maximum weight load it can handle (when installed on a suitably-rated wheel) at its full rated PSI pressure.

Trailer tires must always be fully-inflated to their maximum rated pressure as noted on their sidewall. Only when fully-inflated to that maximum psi pressure can a trailer tire deliver its rated weight carrying capacity.

The wheel/tire you referenced, Kenda 4.80-12 Bias Trailer Tire/Wheel # AM30660, combines a steel wheel rated for 1250-lbs with a Load Range C tire that itself is rated for 990-lbs at 90-psi. Since the tire is rated lower than the wheel, the lower rating determines the overall capacity of this item, 990-lbs.

expert reply by: Adam R

0

David M.

9/7/2020

I found a second eTrailer page that has a chart which states the tires on my trailer will support D rating of 2,540 lbs at 65 psi. So that’s makes me feel much better but 2540*4=10,160 still doesn’t support the 12,000 GVWR of the trailer. Is there some kind of demand factor used? I find it hard to believe a company like Hudson Brothers would install underrated tires on their trailers. What’s up?

Reply

Jon G.

9/10/2020

@DavidM Make sure that you are checking the weight rating of the exact tires on your trailer as that can vary some between tire manufacturers. Another thing to keep in mind is that there is the tongue weight of the trailer to look at since this load will be directly placed on the vehicle. Your best bet is to look at the weight rating of your axles and make sure that your tires are rated for at least that much. In all honesty it wouldn't be the first time we've heard of a trailer company saying one rating and then putting equipment on that doesn't quite add up. That's a question you'll have to ask your trailer manufacturer though just to be on the safe side of things.

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Jon G.

9/10/2020

@DavidM Make sure that you are checking the weight rating of the exact tires on your trailer as that can vary some between tire manufacturers. Another thing to keep in mind is that there is the tongue weight of the trailer to look at since this load will be directly placed on the vehicle. Your best bet is to look at the weight rating of your axles and make sure that your tires are rated for at least that much. In all honesty it wouldn't be the first time we've heard of a trailer company saying one rating and then putting equipment on that doesn't quite add up. That's a question you'll have to ask your trailer manufacturer though just to be on the safe side of things.

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David M.

9/10/2020

@JonG No D rated tire I can find adds up, so I'm betting there is some demand calculation they use. I find it difficult to believe Hudson Trailer company puts inadequate tires on their trailers. I'm definitely going to check with them though. I asked the dealer about this and they just said "don't worry, it will be ok". LOL Interestingly, even if using E rated tires I can find none that have a 3000+ rating which is what it would take (4, 3000# rated tires) to support a max trailer GVWR of 12,000#. Thanks for the followup Jon!

Reply

David M.

9/7/2020

Ok, I just ordered a 5 ton Hudson trailer. (12,000 GVWR; trailer 2k, max load 10k) It comes with four ST 225/75 R15 8-PR tires. D rating = 1220 lbs. per another eTrailer web page. In the context of the above my trailer and load cannot exceed 4880 lbs.?!!? Seriously?? 1220*4=4880 lbs. allowable GVWR because of tire rating. Trailer weighs 2000 lbs. Means the largest weight I can haul is 2880 lbs??!? That can’t be right!

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Answer 1

The reason that you cannot find a list of all load ranges and the weight capacity for each in regards to trailer tires is because it will be different for each size. For example, a 205/75-15 tire like part #AM10245 which has a load range D rating…

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Answer 2

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…

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Answer 3

For a tandem axle trailer rated for 7000 lbs, you can use either a Load Range C or D tire. Each axle will be rated for 3500 lbs so you need a tire that will carry 1/2 that capacity. That would make your minimum load range before limiting your…

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Answer 4

The difference between load ranges varies based on the tire size and brand. When comparing two tires of the same size and brand, a load range D tire will always have a greater weight capacity and psi rating than a load range C. However, when…

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Answer 5

Load ranges are basically an easy way to organize trailer tire capacities. They will vary based on the tire size. For example a Load Range C tire in the 4.80-12 tire size like the part #AM30660 that you referenced has a 990 lb capacity at 90 psi. A…

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Answer 6

Your calculations are correct, your tire capacity is 7,040 lbs. You always want to go with the lowest rated component in your towing setup as your overall towing capacity. So if you check your trailers overall capacity and it is lower than this…

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Answer 7

Load range B trailer tires are going to have a lower capacity than C load range tires. Basically that, psi rating, and the ply rating are the only differences. A higher load range tire would last a little longer than lower load ranges of the same…

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Answer 8

The 5.30-12 tires, being wider, are going to make more contact with the road. This means that the noise, and heat build up will be higher than a 4.80-12 tire but the rolling resistance will actually be less because the tire is larger diameter. The…

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Answer 9

The two sizes you mentioned are pretty similar and fit many of the same 15 inch wheels. The 205/75-15 fits rim widths of 5 inch to 6-1/2 inch whereas the 225/75-15 fits widths that are 5 inch to 6 inch. The 205 is 27.1 inches tall and the 225 is…

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Answer 10

Looking at the BAL Retract-A-Spare it has a much different design than the Lippert Spare Tire Winch #LC159056 you found. You may be able to mount the new winch so it will still work on your trailer but as we do not have both the products here with…

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Answer 11

The most common tire size people go to from the 4.80-12 is the 5.30-12 like the Taskmaster 5.30R12 Radial Trailer Tire #TT53012C. This will give you a width increase of 1/2 inch and a diameter increase of 1.4 inches. This tire also has a speed…

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Answer 12

Generally speaking, a trailer tire will wear in the middle of the tread when it is over-inflated, however that does not appear to be the case with the tires on your trailer. With that being said, I do not recommend lowering the pressure on the tires…

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How to Select Trailer Tires with Correct Load Range Rating for Trailer Gross Weight

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