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

[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?

[chuckster57]

As far as I can tell, your thinking is on track.

[MarkEHansen]

I would really like to be prepared with specific tire options if I should lose a tire while on the road. So far, I have the Carlisle, the Goodyear Endurance and the Maxxis M8008 (which I'm having a hard time finding for sale anywhere).

Based on what I've read here, these seem like good choices. Are there any others I should consider in case the above are not available at the time I need them, or just take whatever is available in a pinch?

[MarkEHansen]

As a follow up, if I look up the Carlisle tires on the Walmart site, I can see they are load range E, but I am not shown the load index. Do I assume if it's a Carlisle 225/75R15 Load Range E, that it is the same exact "ST225/75R15 Load Range E" tire seen on other sites? Or do they make multiple Load Range E tires with different Load Index values?

[tech740]

Originally Posted by MarkEHansen

As a follow up, if I look up the Carlisle tires on the Walmart site, I can see they are load range E, but I am not shown the load index. Do I assume if it's a Carlisle 225/75R15 Load Range E, that it is the same exact "ST225/75R15 Load Range E" tire seen on other sites? Or do they make multiple Load Range E tires with different Load Index values?

They will be the same. Walmart usually has good prices on these tires. I bought a set for my last 5er. They were a great tire for me. Tracked true and took very little weight to balance. I would run them again if I could run that light of a tire.

[sourdough]

LRE will be LRE in that size. Maxxis tires are generally hard to find; VERY hard to find in my neck of the woods. I'm not sure about Endurance availability as being "in stock" everywhere but it seems they are becoming pretty common most places. Carlisles are the same.

As far as your trailer and the OEM Trailer Kings, I'm of a mixed mind on that. I dislike TKs tremendously. On the other hand once RVIA upgraded tires to include a 10% cushion your tires appear to support your weight adequately where as before those tires would have been inadequate. Hopefully the TKs will give you good service and not cause problems. Keep the Carlisle and Endurance info with you in the event of a failure. If I had a failure with them I would replace them all, right then, right there. Oh, yes, it seems your thinking is on track.

[MarkEHansen]

Yeah, that's our thinking. Keep the current tires and treat them well (keep them inflated property and we use a TPMS, etc.) and if we have problems, replace all 5 with one of the above alternatives. At least until they age out, then we'll replace them anyway.

[notanlines]

Mark, I have a completely different school of thought. Why not replace them now and travel in peace. Every mile you put on those garbage tires is a risk. Replace them now and put them on a utility trailer.

[LHaven]

Hah! I'm involved i precisely the same activity at the same time with the same model trailer, so I'll chime in here.

I had the thought that as long as I was going to buy new tires, I'd buy one step beefier if possible, just for the road reliability (not to carry any more weight or anything), but my understanding was that some of these tires may run higher than the 80psi the current TKs are speced for.

I just went through the exercise of unmounting a wheel to get at the markings inside, because my understanding was that those markings would tell me what pressures the rim would handle.

All I could find were 15x6J M2, A1509, and MAX LOAD 2860 lbs... plus a couple of hieroglyph looking markings that look like a stylized angled tread with "17" and a stylized perpendicular tread with "18".

My current TKs are ST225/75R15 E. Is there anything more heavy-duty that it wouldn't be a problem for me to run?

[sourdough]

Originally Posted by LHaven

Hah! I'm involved i precisely the same activity at the same time with the same model trailer, so I'll chime in here.

I had the thought that as long as I was going to buy new tires, I'd buy one step beefier if possible, just for the road reliability (not to carry any more weight or anything), but my understanding was that some of these tires may run higher than the 80psi the current TKs are speced for.

I just went through the exercise of unmounting a wheel to get at the markings inside, because my understanding was that those markings would tell me what pressures the rim would handle.

All I could find were 15x6J M2, A1509, and MAX LOAD 2860 lbs... plus a couple of hieroglyph looking markings that look like a stylized angled tread with "17" and a stylized perpendicular tread with "18".

My current TKs are ST225/75R15 E. Is there anything more heavy-duty that it wouldn't be a problem for me to run?

CD, been a long, ugly day and my battery is about out but since you are in that predicament...and I don't like TKs, I'll post a couple of thoughts and others can chime in.

Your wheels are rated for E tires. There are lots of E rated ST tires and TK would not ever be on my list for a replacement. I did not take time to pull up your trailer or its specs but assuming the E is going to give you adequate cushion. In that case I'm thinking at least upgrade to the Carlise Radial HD LRE. I also believe someone mentioned that one of the manufacturers is now making a steel cased tire in that size...maybe Cal? Hopefully they will chime in. I'll check back tomorrow and good luck.

[LHaven]

Now that my memory has loosened up, I recall that what I did when I went through this exercise on my last rig about 15 years ago to beef up my tires was to climb up a step in load rating. But in this case, it looks like I'm already at the top load rating for this size tire, so I guess there's not much I could do to get a more robust compatible tire. (Well, other than change brands, of course -- I'm doing this precisely to get rid of the Trailer Kings.) I will look forward to hearing about those "steel cased" tires if someone responds.

I see those Carlisles available at tirebuyer for $86, a far cry from the Goodyears that are running around $135 each. I'm a little surprised at this, but if there's some massive discrepancy in the specs, I'm missing it.

Thanks.

[JRTJH]

The Carlisle Radial Trail HD and the Goodyear Endurance are, for the most part, direct competitors with very similar tire construction...

The 225 75R15 LRE size is both brands will carry 2830 lbs @ 80PSI. That is also the maximum weight limit for your wheels, so installing heavier duty tires that require a higher pressure to achieve that bigger load rating would not be compatible with your current wheels.....

There are several "steel cased ST tires" in the 225 75R15 size. The Trans Eagle All Steel ST is one brand: https://www.bestusedtires.com/transe...SABEgJijvD_BwE It's a Load Range G (14 ply) tire with a load rating of 124 which is 3527 pounds @ 110PSI. Your wheels would not carry that pressure or that load, so to use such a tire, you'd also need 4 new wheels. At $500 for the tires and probably another $500 for the wheels, then the "next weakest link would be the bearings/hubs and axles...

When does the "upgrading" stop ???? It's easy to "spend someone else's money" but if it were me, I'd buy the new Carlisle RT HD's, install them on your existing wheels with metal valve stems, have them balanced and save the rest of that money for insurance premiums (in the event of a tire failure)...

[travelin texans]

Originally Posted by LHaven

Now that my memory has loosened up, I recall that what I did when I went through this exercise on my last rig about 15 years ago to beef up my tires was to climb up a step in load rating. But in this case, it looks like I'm already at the top load rating for this size tire, so I guess there's not much I could do to get a more robust compatible tire. (Well, other than change brands, of course -- I'm doing this precisely to get rid of the Trailer Kings.) I will look forward to hearing about those "steel cased" tires if someone responds.

I see those Carlisles available at tirebuyer for $86, a far cry from the Goodyears that are running around $135 each. I'm a little surprised at this, but if there's some massive discrepancy in the specs, I'm missing it.

Thanks.

This is a weird coincidence!
I'm also a member on the Crossroads forum & there was almost the same post going on.
Just this morning I was accused of being "argumentative & trolling" by the moderator when I stated that the GY Endurance tires were "nearly twice the price" of other brands & in my opinion were not necessarily twice the tire. I recommended Carlisles from my experience with them, to which he adamantly disagreed that "GYs are that much better tire & with any of the others you get what you pay for".
Sorry! Enough about me.
Back to your question. Check if there's a F rated tire in your size available, that's one rating above an E. If not the Carlisle in the same size are bound to be better than the TKs.

[sourdough]

LHaven, as John suggested I would go with the Carlisles as well. I put them on my last trailer and really liked them. Didn't think about the steel cased tires going to LRF and higher pressures which wouldn't benefit you with your existing wheels.

[LHaven]

Originally Posted by JRTJH

At $500 for the tires and probably another $500 for the wheels, then the "next weakest link would be the bearings/hubs and axles...

As I mentioned, I'm not really looking to beef up my suspension capacity, I'm just looking to reduce the probability of my tires going boom. Replacing a tire is one thing, but the fact that it usually takes out the wheel well, the skirt and occasionally even the side panel are just unacceptable.

[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?

Almost.


Load range letters are the only official medium for determining load capacity for ST & LT tires. Tire load index numbers are allowed on ST & LT tires to display a speed rating letter. As you can see above the load index 117 for that tire is quite a bit lower than the load range E for the same tire.

Your tires, Designated size ST225/75R15 for trailer service will be built with these load ranges; LRC, LRD, LRE & LRF. They all conform to an identical load inflation chart, meaning the LRF will provide an identical load capacity as the LRC at 50 PSI. Therefore going up a load range does not constitute a change in size. The higher load range just has the ability to carry more weight at a higher PSI setting.

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

Brands are not mentioned in tire industry regulations and standards. ST and LT tires to not have quality grading so a brand choice by a consumer is a personal choice based on their experience or some antidotal information.

[CWtheMan]

Originally Posted by LHaven

Hah! I'm involved i precisely the same activity at the same time with the same model trailer, so I'll chime in here.

I had the thought that as long as I was going to buy new tires, I'd buy one step beefier if possible, just for the road reliability (not to carry any more weight or anything), but my understanding was that some of these tires may run higher than the 80psi the current TKs are speced for.

I just went through the exercise of unmounting a wheel to get at the markings inside, because my understanding was that those markings would tell me what pressures the rim would handle.

All I could find were 15x6J M2, A1509, and MAX LOAD 2860 lbs... plus a couple of hieroglyph looking markings that look like a stylized angled tread with "17" and a stylized perpendicular tread with "18".

My current TKs are ST225/75R15 E. Is there anything more heavy-duty that it wouldn't be a problem for me to run?

Five or six ST tire builders are now building an all steel ST225/75R15. It's a LRF rated at 3200# at 95 PSI.

[CWtheMan]

Originally Posted by LHaven

Now that my memory has loosened up, I recall that what I did when I went through this exercise on my last rig about 15 years ago to beef up my tires was to climb up a step in load rating. But in this case, it looks like I'm already at the top load rating for this size tire, so I guess there's not much I could do to get a more robust compatible tire. (Well, other than change brands, of course -- I'm doing this precisely to get rid of the Trailer Kings.) I will look forward to hearing about those "steel cased" tires if someone responds.

I see those Carlisles available at tirebuyer for $86, a far cry from the Goodyears that are running around $135 each. I'm a little surprised at this, but if there's some massive discrepancy in the specs, I'm missing it.

Thanks.

The increased price for the GY is probably because the China tires have much reduced taxes known as tariffs.

[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).

[JRTJH]

Originally Posted by LHaven

As I mentioned, I'm not really looking to beef up my suspension capacity, I'm just looking to reduce the probability of my tires going boom. Replacing a tire is one thing, but the fact that it usually takes out the wheel well, the skirt and occasionally even the side panel are just unacceptable.

Yep, which was my motivation for writing the "last half of the last sentence":

...if it were me, I'd buy the new Carlisle RT HD's, install them on your existing wheels with metal valve stems, have them balanced and save the rest of that money for insurance premiums (in the event of a tire failure).

Another thought: Since your wheels are the "limiting factor", buying the more expensive steel belted LRG tires and using them as "LRE tires" with 80 PSI/2830 lb capacity, won't provide any more "tire capacity/protection" than the Carlisle or Endurance tires.