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).
The goodyear Marathon's could have their speed rating increased from 65 mph to 75 mph by increasing the cold inflation pressure by 10 psi, this in effect reduced the hysteresis in the tire. Also to note: 49 CFR § 571.110 -. S4.2.2.2 When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle. Nobody seems to actually look at the regulations when spouting off information, they seem to just parrot what so and so told them and what marketing literature they read.
@@N-M424 yes, that 1.1 factor accounts for the difference in the K factor between P tires and ST tires. Notice there is no rerating factor for putting light truck tires on a trailer? They don't have to be derated, but you can't exceed the load rating of the tire. That means in order to switch to a light truck tire, you have to get a physically larger tire, otherwise you will be exceeding it's load rating. As for increasing the speed rating of the Marathon by increasing the inflation pressure by 10 psi, yes you can do that as long as you don't exceed the maximum inflation pressure. Since most tires have to be inflated to the maximum pressure anyway just to handle the load, this is not an option for most people. I am running my tires at 70 percent load rating when under inflated by 15 psi. I can easily increase my inflation by 10 psi. But my tires are already speed rated beyond 65 (you can look it up, they are Goodyear Endurance).
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.
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 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'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.
THANK YOU for another informative video. (Please give me your opinion of TOWMAX tires.) The first improvements that we make to a new camper are a new set of TOWMAX ST tires with the highest LR for the size, WET-BOLTS and EQUALIZER. The rims will be inspected for cracks (experience), the tires will be BALANCED, PRESSURED to the MAX and COVERED when not in use. SO FAR SO GOOD as we tow back and forth across the USA.
Couple things remember, ALWAYS use ST vs LT when possible for trailers . 1- trailer tires generally use nylon in its construction vs the polyester that’s used in Lt and “P” rated tires. Nylon is a very strong material, but tends to flat spot when sitting for a while, resulting in a lot of bumping for the first part of driving till it smooths out. Perfectly normal. However, most people wouldn’t want that on their daily driver. 2- LT tires have to have a higher margin of safety with reference to the load they can carry. I.E : a P235/75r15 (4ply) tire had a higher weight carrying capacity than an LT235/75r15 LR-c (6 ply rating). The 6 ply tire will in reality be able to carry more load than the P (4ply rating) but it’s not marked that way because of the higher safety margin required. (They know people tend to over load these vehicles). The Goodyear endurance tire is excellent. BUT no tire can survive being used with an under air pressure condition. Most of the tires you see blown out on the road are a result of low inflation, whether by a road hazard or driver not checking their air pressure prior to the trip. Remember, the tires CANNOT CARRY ANY WEIGHT, ITS THE AIR CONTAINED THERE IN THAT DOES. Don’t believe me? Find yourself a dismounted tire and stand it up and sit on it. After you fall to the ground, check the sidewall and see what its “carrying capacity “ was…
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
Years ago, the Goodyear G614 LT tire, which is rated as a trailer tire only, was the only 14 ply tire that was available for RV use, and was a great but expensive upgrade from the Chinese 10 ply Goodyear tires. We are now using the Sailun 14 ply S637 tires on our fifth wheel RV, and are very happy with them. If Goodyear changed the G614 to an ST rating, they might not have to change anything in their construction and would be able to rate them with higher weight capacity.
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.
I wouldn’t hesitate not one second on upgrading to a 225. Just check your clearances with the tires that you currently have. The 205 is 27.1”D x 8.1”W. The 225 is 28.3D x 8.9”W. You’ll basically be looking at 1/2” difference when it comes to clearance. Most clearance issues that i have seen are usually because of the width.
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.
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
Hi Guys I'm in Australia and all the caravan dealers are running LT Tyres on there new trailers. They need to watch this video. Also what are your thoughts on balancing trailer rims??
Trailer tires. I’m confused - I’ve seen on the tire : Load range E 10 ply rating and on the same tire: Plies: tread polyester 2+ steel 2 + nylon 1 What’s up with that?
Somewhere in your audio settings, either during filming, importing, or editing you have the audio set to mono. Its only coming out of the left speaker.
Thanks! Sorry about that. We did have quite a time with our mics not holding our settings. And probably some user error in there somewhere. We have it fixed now in our latest videos. Thanks for watching.
So that "14 ply" ST tire has the same load capacity as the "10 ply" LT tires on my Ford F-250? How can it be said that ST tires are "rated to carry more weight"? I'm pretty well versed in tires, and to me a LT tire that is marketed as being built to handle rock crawling, off road use, puncture resistance, grip in foul weather, and load carrying for a 4x4 with a 10,000 GVWR is PLENTY of tire to handle running straight down the highway on a trailer. I would expect it to have zero issues. And, there are U.S. made LT tires everywhere. Try finding a U.S. made ST tire....
Why do I have more blowouts with ST tires than with LT tires on my trailers? I had 2 ST tires blow on 1 trailer and both times it was empty and parked when they blew.
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 had several ST trailer catastrophic blow outs . I have never had an l.T tire blow out on me ...... I'D like to put LT tires on my trailer ,,,thoughts????
Hello. What about 13" tires. There is not as good of a selection. I have a folding pop up trailer, under 2000 lbs. I have recently switched to bias ply tires to see how they perform. The trailer tends to wear the tires unevenly on the inside, no matter what inflation I have them. I recently had a separation on an older, fairly worn radial. It did some minor damage, thank goodness I stopped before it did more.
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.
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 totally understand what you’re trying to achieve! There are several off-road camper style trailers on the market that use a tire set up like you’re wanting to do b/c they use them primarily in off-highway situations. I don’t disagree with that. They may be helpful if you will be in the sand a lot, just be sure to double check your load ratings to make sure they are sufficient for the weight you’re hauling.
@TheTrailerSmith thank you for the swift reply.. My trailer was shipped with 3500 lb tires. The ones that I'm looking at are 3800. I was concerned about the width of the tires shopping around I noticed that most trailer tires are narrow and figure there is a reason for that
Did you discuss tire life? Top end tire doesn't help if you age out before you wear out. Typical tire life is 5 years. Rv tires will almost always age out before you ever wear them down.
Well….I can’t claim that it’s comfortable for 13 hours. 😁 But it’s pretty good for 9-10 hours and bearable for the remainder of the day. It’s a Twisted X chukka style boot so that’s probably why it’s as comfortable as it is-it’s not technically a work boot.
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?
Always check cold tire pressure and it is taken into account for the recommended pressure. There are some exceptions: in extreme heat with heavy loads the tire pressure can get too high. If that is the case, it would be necessary to bleed some air out. Great question! Thanks for watching&
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
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.
It’s not necessarily an upgrade. I can only speculate about why they are installing LT and leading people to believe it’s an upgrade. What I will say is that you can buy cheap LT as easily as you can buy cheap ST. When I see RVs with an LT tire from the dealer, they are generally cheap LT.
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.
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.
One blowout can easily cost you more than $800 ! I am also a huge proponent of TPMS on all my trailers. Won't always help, but It's a great early warning system. Saved my butt a few times now.
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.
Could you address the tipic of balancing trailer tires. I recently bought a new dual axle dump trailer. When empty, i noticed at certain speeds i could feel a vibration. I took it to a tire shop. They said trailer tires don't need to be balanced. I took it to another shop and said yes, balance them. The vibration was gone.
I was going to post that question also. Many still believe you don't need to balance trailer tires and that may be true if you only tow in town. ON the highway at 70 MPH those tires are spinning pretty fast and can lead to unwanted vibrations .I have always balanced my tires.
My manual for 2019 Montana 5th wheel state that they do not need balancing. I still balance it though, but find it odd that it states that you don't need to
I run LT tires on my 5th wheel . They are rated Steer, drive and trailer in there literature. I do not exceed the weight rating. (LT tires have a larger safety factor than ST tires for weight capacity. ) I can get 2.5-3 times the tread life from the LT over the ST. In a 235/80/16 the LT sidewall is stiffer than ST of same size and ply rating. I pay attention when parking to try and not turn any sharper than necessary as more duress is added to suspension with less flexible sidewall on tight turns ( forward or back) If you cover a lot of miles, LT tires have proven to be far superior tire life with my setup.
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
@TheTrailerSmith I am surprised that you didn't mention tire date codes in your two excellent videos on trailer tires. While I'm not an expert, I'm a total towing nerd that enjoys towing well, and I use tire date codes to track tire age. Based on the miles I put on my trailers, they "age out" well before they wear out.
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?
I have an air question, we live and travel in hot climates with 11,500 lb travel trailer using Hercules 225/75/16 tires. It says cold inflation 95 psi for 3000lb max. It’s 75 in the morning and 90s as we’re traveling tst shows tire psi increase from 95 to 107 are we ok?
Should cover if balancing a trailer tire is necessary or not. I'm a believer that it is not. I've changed hundreds and hundreds of semi trailer tires and not a single one was ever balanced in any way. That and even new trailer tires mounted on rims do not come balance. Just my opinion and would like others who know what they are talking about or have a lot of experience with trailer tires chime in.
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
@@joeclark9042 Oh! The boots are Twisted X amzn.to/3wC4Cpi I don't wear the steel toe in this particular boot so I always have to make sure I avoid that.
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.
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.
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.
The trailer manufacturer should have put a sticker on the trailer telling you tire size and tire pressure. The sticker will tell you the original tire size and that's a good place to start.
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
@Grayson.84 gonna guess it's a motorhome with that size tire. Regular travel trailers, cargo trailers fifth wheels seem to all have China bombs. Wife just bought used class c with cooper's, we'll see how they work out. Probably need replaced next season due to age
