Just want to understand the load/weight rating requirements for replacement tires

[MarkEHansen]

Originally Posted by MarkEHansen

CWTheMan: When you say: "Bottom line: Replacement tires MUST provide - via inflation - a load capacity equal to or greater than what the OE tires provided."

Is that referring to "Load Range E" or the "Max Load" stamped on the side of the tire?

Since my current tires have a max load of 2,833 lbs, does that mean that any replacement tires must support 2,833 lbs or better?

If the Carlisle tires had a max load of 2,820 then I would not be able to use them? (I realize this isn't the case, but just looking for the correct rule by which to shop for tires).

Oops, what I meant was that the max load stamped on my current tire is 2,860 while the Carlisle appears to have a max load of 2,833. Does this mean the Carlisles don't meet the requirement (of >= the OEM tire max load value)?

[CWtheMan]

Originally Posted by MarkEHansen

Oops, what I meant was that the max load stamped on my current tire is 2,860 while the Carlisle appears to have a max load of 2,833. Does this mean the Carlisles don't meet the requirement (of >= the OEM tire max load value)?

I explained earlier that you have to use the load range letters for ST tires, not the load index numbers.

[JRTJH]

Originally Posted by MarkEHansen

Oops, what I meant was that the max load stamped on my current tire is 2,860 while the Carlisle appears to have a max load of 2,833. Does this mean the Carlisles don't meet the requirement (of >= the OEM tire max load value)?

It "goes by what's on the tire decal attached to the trailer, not what's stamped on the tire sidewall. The trailer manufacturer determines the tire size, load rating, pressure and provides that information to the buyer by attaching a "permanent decal" with the trailer VIN and all the tire information to the trailer... That's the "must follow" data, not the tire manufacturer's mold die that's cast into the rubber.....

[Roscommon48]

the bottom line is when you buy tires next time you need to look at 'E' rated trailer tires at that same size. everything else is more technical.

[vancouverbrian]

I purchased my Cougar RLS 30 5th wheel and did not like the factory tires. I researched the E rated tires (same rating as factory), and chose the USA made GY Endurance. With the GY tires, came an increase in speed rating. Most are max at 65mph but these tires are rated to 80mph. I never go over 65 but felt that it had more strength. And being USA made, I felt safer. I never want to have a blowout on the road and for me, the feeling of being safer, made the difference. This should never be about increasing payload of the trailer as that can never change from the number on the trailer. But peace of mind is priceless. Just my opinion.

[Mikelff]

One thing that will help you avoid blow outs is a TPMS. It gives you live tire pressure and temperatures. It should warn you before the blow out happens. Even if you pick up a nail it will let you know your pressure is dropping before you shred a flat tire and cause significant damage.

[LHaven]

When I was looking last week, I don't think any of the E-rated tires I found weren't rated to 80MPH. (Tire Kings were not an option, natch.) Due to this week's disastrous venture into wokeness by Goodyear, my Carlisles will be arriving tomorrow.

[CWtheMan]

When requesting information about your tires you have to mention the tires designated size, not just some tire that is "E" rated. All ST tires load capacities are standardized to load range letters by designated tire size. For instance, generally all LRE radial tires will provide their maximum load capacity at 80 PSI. The ST225/75R15 LRE provides 2830# of load capacity at 80 PSI. The ST235/85R16 LRE provides 3640# of load capacity at 80 PSI.

All original equipment tires MUST conform to FMVSS standards. The "bottom line" minimum standard for RV trailers is the certified GARW capacity. Any OE tire fitted to an RV trailer axle must have a load capacity equal to the certified GAWRs. The standard says the vehicle manufacturer must set a recommended cold inflation pressure for OE tires that is appropriate for tires fitted to that trailer.

The standards have never required RV trailer tires to provide any load capacity reserves.

[LHaven]

As long as we're on this topic...

What does it mean when your rim has absolutely no inside markings?

I removed the Trailer Kings from my Cougar and I'm having them installed on my small horse trailer because the tires on it are 13 years old (it hasn't been used in almost that long). I looked on the inside of its rims to see what I ought to use for an inflation pressure, but they are absolutely smooth. Is there some "default" load rating for unmarked rims?

[MarkEHansen]

My utility trailer (Thule) came with a sticker which I placed where they told me to place it. Within a very few years, it is unreadable I really wish I had taken a picture of it before I placed it on the trailer.

[CWtheMan]

Originally Posted by MarkEHansen

I have a 2019 Cougar Half Ton 26RBSWE which came with Trailer King tires.

The tires are load range E, but I'm curious about the rest of the markings on the tire. Here is what I see:

ST225/75R16 117/112M

I get the first part, and I think the second part decodes as:

117 = load index single, which is 2,833
112 = load index double, which is 2,469
M = Speed rating 81 MPH

I also see on the tire the following markings:

Max Load Single 2,860 lbs AT 80 PSI Cold
Max Load Dual 2,470 lbs at 80 PSI Cold

These seem to line up.

I assume that the single/dual is based on how many wheels are on each end of each axle. My trailer has a single wheel on the end of each axle, so I would use the "Single" rating.

The load range on my current tire is E, which all I can find means 10 Ply. When shopping for new tires, do I need to make sure they are at least Load Range E as well as a load index that is large enough to support the weight of my trailer (plus a reserve)?

For example, the Carlisle Radial Trail HD in my size and load range E shows a load index of 117M (so, 2,833 lbs and 81 MPH). This seems like a good replacement tire.

Am I thinking about this correctly?

The load range lettering system is the only official load capacity system applicable for ST & LT tires.

Here is a little history why the load index numbers are on the ST sidewalls. A few years ago (5-7) the government gave the China ST tire manufacturers an ultimatum; They had to start showing a speed limit for the tires they imported into the USA. Or, suffer higher tariffs. There are two ways for them to comply; add the load index numbers followed by a speed letter or mold a speed rating into the tire's sidewall. Most chose the first option. However, they had to do a lot of engineering because the default maximum speed for a ST tire without a published speed limit is 65 MPH. The manufacturers dilemma was compounded by the fact there is no speed letter for 65 MPH. Using a "J" speed letter (62 MPH) was going to be a hard sell so most of them did some retesting of their tires and used the load indexing system to display the speed letters. Most of them started off with the largely accepted "L" for 75 MPH. Now a lot of them are up to the "N" letter, 87 MPH. The only tire manufacturer that I know of that has not identified a speed rating on their ST tires is Maxxis. They can tell consumes it's higher than 65 MPH but without publication their ST tries default to 65 MPH.

If your tires are in fact showing a maximum load of 2860# there are two answers. The tire manufacturer has upped their load capacity for those tires and informed NHTSA of the increase for their brand; or it's a miss print. The official LRE load capacity for those tires is 2830#.

There is precedence in the ST tire marked for the same designated size tire at a specific load range letter, to differ in load capacity. The ST235/80R16 LRE is the example. That designated size may have load capacities of 3420#, 3500#, and 3520#, all LRE at 80 PSI.

[MarkEHansen]

Here's the sidewall showing the Max Load value.