Trailer Tires... Construction Differences from Regular Tires

[Boomer]

While I don't currently trailer, I always wondered what the internal differences are between a trailer tire and a "normal" tire that you would run on, say, a pickup truck. Are the cords different? Are they placed differently within the tire carcass? Is the rubber compound different? I was struck by the fact that they tell you not to run a normal tire on a trailer so there has to be a reason. I don't really see the difference between doing this and running tires on the rear axle of a FWD vehicle.

Thoughts? Comments?

 

[CapriRacer]

Let's start with differentiating between P type tires used on smaller pickups and passenger cars and LT tires used on heavy duty pickups and vans

Difference between P type tires and ST tires: P type tires are inflated to 35 or so psi. ST tires can be inflated to over 100 psi depending on the Load Range. That inflation difference requires a stronger carcass to contain the air pressure. It is this difference that people are usually referring to when discussing the difference between trailer tires and regular tires.

In other words, the primary difference is that ST tires are built with stronger materials.

Please note: Do NOT confuse the max pressure between these 2 types of tires. P type tires are done differently due to speed ratings - and that's where it gets complicated. Suffice it to say that a P type tire with a max pressure of 51 psi (They come in discreet intervals!) is not the same as a Load Range C LT or ST tire (50 psi rating). A LR C would be built stronger.

Difference between LT and ST tires: For the carcass, you could argue that there are no differences - but more properly, there are differences in the construction between Load Ranges, but those differences are common for both LT and ST tires.

While there are differences between ST and LT tires, the differences are in the details that allow each type to function better for their intended purpose.

The net is that an LT tire can be used in place of an ST tire, but not the other way around. But here is where it gets tricky: ST tires are rated for about 20% more load capacity for the same size and inflation pressure. This difference is caused by differences in the way these 2 types of tires are rated - in particular, trailer tires are not powered, and originally, they were speed restricted to 65 mph. The differences are NOT caused by differences in construction.

The way this works is that IF an ST tire does NOT have a speed rating, then the tire is restricted to 65 mph, but if it does have a speed rating, it is restricted to the speed indicated by the speed rating.

I expect a lot of questions. Post them below. I'll do my best to answer them.

 

[930.engineering]

.
What kind of trailer? Generally passenger car tires can be run
on trailers IF they meet the load rating required.

 

[Boomer]

Thank you both. Very interesting information!!

 

[Rmay635703]

I had ST tires on the front of my old Dodge 1500 2wd as they were the only thing available in my size at the junkyard (truck did not require LT tires)

They wore out quickly then weather checked

Otherwise nothing much to report, I was surprised to end up with ST tires after mount but at $25 a tread I couldn’t complain much

 

[samven]

I would think that you could use an LT tire if it meet the load capacity rating for your trailer but you may need to limit your speed and run the full sidewall pressure just as you are suppose to do with ST tires. You need the extra sidewall stiffness that ST and LT tires provide to stop your trailer from bouncing and swaying. P rated tires are designed to give you a softer ride by running lower pressures and softer sidewall. I was forced to run a P rated tire on a boat trailer once. They exceeded the load requirements and I pumped it up to the full sidewall pressure of 41 psi. It was the scariest tow I have ever done. The boat would sway with every slight cross breeze and seemed to come completely off the ground everytime I hit a bump or pot hole. It felt like it was on really squishy springs without any shocks. I only had to go 20 miles but I had to pry my finger from the steering wheel when I got home.
Also you may notice that your ST tires are suppose to be run at 65 or 80 psi, you will need at least an E rated LT tire to get the same air pressure and stiffness.

 

[c502cid]

I finally got so tired of trailer tire issues I went to LT tires on all my trailers. Issues gone.

 

[CKN]

.
What kind of trailer? Generally passenger car tires can be run
on trailers IF they meet the load rating required.

I can tell you don't tow. You cannot put a boxed travel trailer on passenger tires. Google is your friend in to why you shouldn't. It always marvels me how we get non-towers chiming in on these thread posting false information.

 

[930.engineering]

.
You missed the fact the OP didn't say he's planning on pulling a 'boxed travel trailer'
or even something like that. Perhaps he'd just wants to carry off some garden waste.
.

 

[Rmay635703]

I can tell you don't tow. You cannot put a boxed travel trailer on passenger tires. Google is your friend in to why you shouldn't. It always marvels me how we get non-towers chiming in on these thread posting false information.

I have (as a spare) put a passenger tire on a heavy boxed 4 wheel 18’ enclosed trailer used for concessions, had load distribution hitch, trailer brakes and ended up staying on 5 years, wore well compared to the st treads in the other positions

Trailer rarely exceed 65 to conserve fuel,

I would have to test the trailer with them all around to make sure it tracked properly,
I also had a 10’ enclosed wide body crap single axle with passenger tires loaded up to max payload trailer was fine with load distribution,
Trailer never towed or backed well with ST or passenger tires, (tracked but was too heavy on the hitch and took more go power to move than the larger trailer) can’t say I could tell the difference between tires in the 70000 miles I pulled it around the state.

Likely a situational awareness issue if you can’t tow because of the tire choice , but you do need enough tread to support the load, see lots of blown 8” tires and ripped up 8” rims everywhere on overloaded things going 85mph

Occasionally find a blown 8” tire still connected to the hub.

 

[SwampSurvivor]

Likely a situational awareness issue if you can’t tow because of the tire choice , but you do need enough tread to support the load, see lots of blown 8” tires and ripped up 8” rims everywhere on overloaded things going 85mph

Occasionally find a blown 8” tire still connected to the hub.

My coleman popup camper had the 4.80-8 tires on it. I bought 3 new ones and put them on. Definitely didn't like over 55 with them .. they got HOT. Never blew one out but I kept it at 55.
I put 4.80-12 on it and those were fine for 75 MPH all day.

 

[Fabulous50s]

Gotta think about the RPM of those little 8" wheels, crazy fast.

 

[Fabulous50s]

Pretty much every video i watch about RVers is that when they were sick of having the blowouts and put LT tires on all the problems went away.

Thinking of doing the same, aa the tires on my RV are well over 10 years old and weather cracked. LT tires will go on it.

 

[ls1mike]

I have been towing a travel trailer/boat/flat bed for the past 16 years. The current trailer has been towed just over 44,000 miles.
ST tires don't generally wear out because of tread. They age out. I change mine every 4 years. Most are only rated to 65 mph.
Some are to 81 mph. I have a set of Carlisle Radial Trail HD. They are rated to 81 MPH. They are the best set of ST tires I have had on
a trailer. I have never had a blow due to tire failure. I did pick up a nail once which caused a failure. Keeping them properly inflated is
probably most important thing to do when running an ST tire. Keeping them covered in storage helps as well. The ST tire also has a side wall that allows more flex and bending for getting into tight spots so you are not putting all the pressure on the wheel bearing, which on my 32 foot travel happens often. You should see those sidewalls flex.

Having said that I know a bunch of people who run LT tires on their heavy/full time 5th wheels. Most of those guys cannot run those
tires at full pressure as the rims are not rated for it. A few have upgraded their rims. The guys who do not run them at full pressure, that I know, have never had an issue. You just have to make sure they can support the weight. I can't say I know anyone who runs LT tires on a bumper tow travel trailer, flat bed, or utility trailer. Does not mean it doesn't happen. I just think in those cases the ST tire is cheaper and they are not running them full time.

 

[CapriRacer]

Pretty much every video i watch about RVers is that when they were sick of having the blowouts and put LT tires on all the problems went away.

Thinking of doing the same, aa the tires on my RV are well over 10 years old and weather cracked. LT tires will go on it.

In 2017, Goodyear introduced the Endurance line of ST tires. Since that time, I have only heard about a single ST tire failure. I think the industry has stepped up and successfully addressed the issue and the need to use LT tires on trailers is gone.

 

[nthach]

I’ve actually seen a VW Vanagon on trailer tires. The stock 185R14C tires for those are hard to find in a LT tire until recently as a grey market Hankook import.

I’ve seen very questionable Chinese-made tires on trailers heading from the local port

 

[CapriRacer]

I’ve actually seen a VW Vanagon on trailer tires. The stock 185R14C tires for those are hard to find in a LT tire until recently as a grey market Hankook import.

Ah ..... Mmmm ... How to explain this?

A 185R14C is a C type tire. It's the European equivalent to an LT tire. And both LT tires and C type tires can be used on trailers. (P type tires, too, if you derate the P type by 10%!)

 

[nthach]

Ah ..... Mmmm ... How to explain this?

A 185R14C is a C type tire. It's the European equivalent to an LT tire. And both LT tires and C type tires can be used on trailers. (P type tires, too, if you derate the P type by 10%!)

I meant the tires were explicitly marked as trailer use only.

 

[spasm3]

I have been towing a travel trailer/boat/flat bed for the past 16 years. The current trailer has been towed just over 44,000 miles.
ST tires don't generally wear out because of tread. They age out. I change mine every 4 years. Most are only rated to 65 mph.
Some are to 81 mph. I have a set of Carlisle Radial Trail HD. They are rated to 81 MPH. They are the best set of ST tires I have had on
a trailer. I have never had a blow due to tire failure. I did pick up a nail once which caused a failure. Keeping them properly inflated is
probably most important thing to do when running an ST tire. Keeping them covered in storage helps as well. The ST tire also has a side wall that allows more flex and bending for getting into tight spots so you are not putting all the pressure on the wheel bearing, which on my 32 foot travel happens often. You should see those sidewalls flex.

The wide trax axles that are further apart really seem to load the sidewalks when making tight turns.

 

[ls1mike]

The wide trax axles that are further apart really seem to load the sidewalks when making tight turns.

I do have those, but it is nice for towing.