There is one little known difference between LT and ST tires. If you were to take an LT tire and change the mold to do only one thing -- designate it as an ST tire, its load rating would automatically increase. If you go to search the National Highway Traffic Safety Administration website, you will find a publication titled "The Pneumatic Tire". Chapter 5 is all about load rating and how it is calculated. They discuss something called the K factor, which is different for ST, LT, and P metric tires. That is how you can get two different load ratings for the same exact tire just by changing its designation from LT to ST. It is possible to run LT tires on a trailer, however, very few people seem to be smart enough to do so safely. When a person goes to replace their trailer tires, their decision on what to purchase is based on two factors. The most important is price, and a lower price wins nearly 100% of the time. The second factor is physical size. If you replace an ST tire with an LT tire of the same physical size, you will most likely be running the LT tire above its load limit. There is another safety issue . . . trailer sway. Often the sidewalls of LT tires will have more flex to them, which can contribute to trailer sway. This does not appear to be much of an issue on 5th wheel trailers but could be a big problem on a travel trailer. Switching to LT tires often requires upsizing, including upsizing the wheels. Although I did this on a 5th wheel trailer I once owned, I don't recommend people try it as there is more to know and understand to do it safely than the average trailer owner is willing to learn. There is also a lot of bad information available on the internet to help them make poor decisions. Back around 2012 there was a thread on RV.NET started by a tire engineer by the name of Barry Smith. Roger Marble (a retired tire engineer who had specialized in failure analysis) also participated in that thread. Barry was digging into the issue of the perceived high rate of trailer tire failures at the time, even though he had no skin in the game. It was just professional curiosity on his part since he was an engineer for a major North American tire manufacturer (who did not make trailer tires). His conclusion, after a record 700+ posts in the thread was that trailer tires were probably a little overrated and most users were running them on the ragged edge. His recommendation was to not load them beyond 80% of their rated load capacity. This became known as the "80% rule". Since then, Goodyear appears to have addressed the issues plaguing the trailer tire industry by developing the Endurance line. One of the significant differences you will find between a Goodyear Endurance and just about any other ST trailer tire out there is that it has a higher speed rating (not that you want to tow at those higher speeds). As Roger and I discussed in that thread, the issue is heat generation in the tire. Once the rubber gets to a certain temperature, it breaks down and you have a failure. The flexing of the tire as it contacts the road and the friction generated when it contacts the road both generate heat in the tire. As the tire is no longer contacting the road, it starts to cool down until it contacts the road again. At slower speeds there is adequate time between contacts with the road to remove the heat that was generated by the tire/road interface event through air contact cooling. As you speed up, there is less time for that cooling to take place. At some speed, you generate more heat than gets removed by the cooling, resulting in a tire failure. The more you load the tire, the more flexing there is and thus more heat generation. Running the tire underinflated results in the same. Barry's 80% rule was simply a way of reducing the flexing and thus the heat generation. Goodyear seems to have developed rubber that can either withstand higher temperatures or generate less heat when it flexes (maybe a little of both).

Great videos and great info! I toyed with the idea of getting LT tires for my towable RV but went with the Endurance. 4 years and still going. I also use tire covers and TPMS. Still look like new.

My cargo trailer is about 7 years old. I've only run it less than 3k miles, and I keep it inside. I have a use for it now, moving out of state. I got rid of the Kenda Karriers that were on it and added Goodyear Endurance tires. It was about $800 for all 4, but that peace of mind is priceless.

For me, the trailers I pull are 75% or more loaded to maximum capacity. I’ve found out through many blowouts that run the best possible tire I can get. And have a spare tire of the best. I run mainly highway. And I always check pressure before I leave out and every time I stop first thing I do is check hub temperature. I really enjoy your videos.

Great information! Thank you

The best trailer tires I found are usually in the ditch next to the freeway. Some have a hub or drum with a toasted outer bearing race. Some have lug nut holes that are "oversized" from running loose. Some have a blown tire with a good wheel. Some still have the broken spare tire mount bolted to the wheel. Either way it gets the junk off the road.

I use a tpms on my trailers. That’s peace of mind being able to monitor heat and pressure.

I've got 3 single axle trailers, I get the highest load rating in the 15 inch category ST tires I can afford. Compared to replacing fenders and other damage its not a bad deal. Always check tire pressure before pulling along with lights and coupler. I don't go much past the 5 year mark, I've stretched it for a few short trips. A spare tire is a must! I'm kicking around the idea of putting brakes on the biggest one. I don't use it much, but when I do I know its going to be heavy. Great videos good information.

Thanks for the video and all the information you shared with us! Does the ST rating recommendation apply to small offroad trailers (600lbs to 1,200lbs dry weight)? Like the Tentrax (fiberglass, 600lb dry weight, maybe 1,200lbs loaded) trailer, for example. These trailers see paved roads as well as rocky, sandy, and muddy terrains.

I have a small utility trailer and put my replacement set of tires on it. I bought Gladiators and they have been an excellent tire. Heavy loads high speeds and no failures. But I also check the air before each use. And I know they have been overloaded many times when I have loaned my trailer out to friends

We went from Trailer Kings to Carlisle. We’ve been running the Carlisle tires for 3 years now and have had no trouble out of them. Side note we keep covers on them to keep the sunshine off them.

When i bought my new car hauler trailer 15 years ago i bought it with used P car tires on it to save $200. It worked out for me. They were underrated for the total trailer weight. But i didnt haul at the max weight. I got 8 years or so iut of those tires. They were very opd at that point. I replaced two when they were really bad and left two. One finislly blee out and i bought two more. I bought E range tires for it at that point.

How good are Kenda Karrier Tires?

Been anjoying your videos but the sound is only coming through on one side. Pretty sure it's been like that on all your videos that i've watched just letting you know. Glad I found your channel good info thank you

I have always heard that st tires have more give to sideways pull when turning because of the different compound in the sidewall so you have less stress on the tire

What is your thoughts about this? My trailer came with ST20575R15 . Some folks are recommending going to ST22575R15 as they say more tire on the ground is a good thing. Thanks. Your channel has great information.

Got a question I’m getting ready to start a hauling business, any that I can put on an equipment trailer. In a 17.5 size does someone make a true super single. I also have a f650 2007 that has 19.5’s that I would like to think about super singles on. Yes the truck is set up to put on 22.5 from the factory but I don’t want to go any higher on the truck, want to keep the hitch as low as possible.

Good video I really like this I'm going to have to give me some different tires now but anyhow what kind of boots are the ones that were in your left hand

I would believe the reason a MFG using LT tire is to gain side wall flex. This would allow for a softer ride, saving things like frame cracking. There are several differences in ST and LT tires, and your videos come them well. One main difference is the ability of sidewall flex on an LT vs ST. As was mentioned LTs are designed to be smooth riding, turn, and apply torque. STs are designed to hold up a load. Sidewall construction plays a huge roll in those characteristics. I do check my tire pressure every trip. I have run Gladiator tire on three trailers. An 18ft car trailer, 16ft utility, and an 8ft utility for about 15 years, replacing about every 6, with great success. Great video with well thought out and presented information. Your passion for the safety of your viewers and motoring public comes through. In my humble opinion.

👍👍

I drove to the tire shop frist and replaced with Goodyear endurance , no trouble what so ever.68000 k later ,change to Carlisle's st,have 30000 k on them still look new.cheers

Thank you for all the tire information it was very helpful, but can you tell me what boot you wear for 13 hours and still find comfortable?

Can you do a video on tire pressure? I can’t seem to find a straight answer on some questions I have. Like how much should the pressure go up when driving? Mine are going up 10-12 psi. How do you determine how much psi in the tires to start? How much psi over cold air max can a tire go? My tires are 225/75-15 Venom Power Primo Hauler G rated 14 ply with 110 psi cold max.

I pretty much agree with everything you said but I have an Airstream camper that came with Michelin LT225/75 R16's. Airstream also puts the same tires on their 30-33 Classics which are anything but an entry level camper starting about 200K. No idea why they went to truck tires on some models but as you can imagine the Airstream forums are full of debate over this. Exceptions to every rule I guess.

Owned three fifth wheels, all had "st" junk tires. Put "E" range LT tires on with no problems. I never air down, run full 80 psi.

i have a question. so i check my air in july when is 90 deg plus pre trip and its 80 psi once im an hr or two down the road do i need to bleed air or is this taken into account when mfg sets the recommended pressure?

My former coworker worked in the tire industry for about 20 years before he came to the creamery where I worked. He told me trailer tires are designed to handle the dragging during turns LT tires are not. Trailer wheels do not steer therefore they drag when the trailer is turning.

What would you recommend for a car tow dolly? Thanks

I’ve found the Duro trailer tires are really good?

Just finished converting a 22ft toy hauler into a camper, We plan on spending a lot of time on the beach soft Sand. The trailer is being pulled by a 2009 Hummer H2 SUT with air suspension. We are considering placing some wider LT rims and tires on the trailer, more than likely the same tire and rim combo as what we currently have on the hummer Trailer Spec: Custom trailer from Rock Solid. tandem 1400lbs spread axle. the trailers Max loaded weight will be no more than 9,000 lbs at any time, currently just over 7,000 lb with 160 gallons of fresh water. Rim: 20" Black Rhino ABRAMS Tires: MAXXIS RAZR MT LT275/65R20 Any advice and opinion would be appreciated we spent a lot of time researching and building every other aspect of our trailer but completely neglected tires until now.

I was always told, if the trailer was a single axle, you could use LT tires (with appropriate weight rating). Single axle trailer tires don't experience the lateral loads on the sidewalls the same as tandem axles. Any truth to that?

Still no information on date codes. Am I missing something?

Where is the super cargo tire made? And where is the Gladiator made

Most of the RV trailer industry are installing LT tires as an upgrade to ST tires.

You dont cover speed rating. The slower speed rating the higher the load rating. Cheaper st tires are dangerous. No sidewall strength. Many st tires have low speed ratings

I will never run an ST tire on anything--only LT tires will do !!!

I had some Super Cargo 205 15 load range D. Tandem axle car trailer. They worked.. Going by date code, they are 4 years old and almost to the wear bars. Replaced em with Free Country also load range D. Look like Goodyear Marithon. Even have the scuff gard. Big trip upcoming. Around 1,800 miles one way. I'll letcha know how well they worked out.