LT vs. ST Tires for RVs: Is Upgrading Worth the Hassle?

[J_Man]

I’ve been watching a couple of threads about different tire brands failing on RVs, and I had a related question but to avoid high-jacking someone else’s post I’m asking this in a new thread.

I have almost no tire brand loyalty, and very limited experience with RV tires. Our 2025 GD 22MLE is relatively light weight, and came with GY Endurance ST205/75R14 tires.

We now have approximately 5,000 miles on our 22MLE with zero tire issues. I expect we won’t (or shouldn’t) need new tires for the next couple of years.

But, I’m starting to wonder what tire I should look for when the time comes to replace the OEM tires.

Are LTs a better solution to replace the STs?

I’m not thrilled to have what I think are ‘smallish’ (14-inch) tire/wheels, so I’m wondering if I should plan to buy 16-in LTs (new rims and maybe brake drum upgrades to accommodate the 6-lug wheels… which may mean new axels) - lots of $$$ and complexity.

Then, my sanity slowly returns and I remind myself that I’m having ZERO issues running the 14-in tires, and going bigger is a total waste of time and $$$.

So, back to initial question: LT vs. ST?

Advice and/or experience would be helpful and appreciated.


J_Man

 

[MtnGuy]

This has been discussed for a long time on different forums. Each side thinks their tire type is the best. Get some popcorn and sit back for some entertaining posts…..including mine of course.

For me, I have been running ST tires for over 20 years on my various travel trailers and 1 5th wheel. I had 1 slow leak and 1 tire that did not wear good over the years.

I intend to continue to run the OEM Goodyear Endurances on my 2024 Imagine 22MLE for 5 or 6 years. If they do good over that time period, I will again have those installed on our trailer.

I ran the OEM Westlakes on our 2017 Reflection 337RLS for 3 years until 1 tire started wearing weird. I had Endurances installed and had no problems except a screw in my tire coming back from a western trip. My TPMS alerted me to the problem, and I had it fixed after getting home. I pumped up the tire every morning and watched the pressure closely. No other problems with that tire while I had the 5th wheel.

I thing I am now doing different now, is not running my tires at maximum pressure. According to the Goodyear tire chart and CAT scale weights, I can run my tires at 35 lbs. Not knowing the side to side individual wheel weights, I compromise at 50 psi each tire. I figure that will give the tires a little more cushion when hitting rough spots, and also save some jarring in the trailer.

 

[el Rojo]

I don't run at max psi either. On a recent trip, I filled to max psi on a cool morning. Later in afternoon the ambient temperature had increased and we got an over pressure alarm. I had to find a place to stop and let some air out to avoid a blow out.

Just my 2 cents. YMMV.

 

[Hit Factor]

...to find a place to stop and let some air out ...

How do you know the high pressure alarm was set to the correct value?

 

[txloser]

LT vs ST. Both sides have had success depending on the tire used. In the Airstream world for example, many use a 16” Michelin. Lots of money for new wheels and tires when people in that world with 15”/GY Endurance are surviving just fine. Some claim a better ride thus less trailer abuse with an LT tire due to softer sidewalls. Some say you need the stiff sidewalls for tandem axle trailer stuff like turning and backing. Due to lateral stress on the tire. So, who knows. Also, some say the stiffer sidewall of an ST help the trailer track a straight line better. Again, I don’t know. Repeating stuff I’ve read over the years. For me, the ST’s have always done well. Another caveat is with vehicles having larger and larger wheels, LT tires in the smaller sizes are getting slim on options.

I’d run what you’ve got at proper inflation/speed and if there’s actually a problem, revisit it at that point.

 

[el Rojo]

How do you know the high pressure alarm was set to the correct value?

We googled it to confirm. Alarm went off 125 psi.

 

[dryfly]

@J_Man

If your trailer is running 14" wheels the first thing you might want to consider is what is it going to take to allow an upgrade to any type of 16" tires. You are going to need the proper spacing between the top of the tire and the wheelwell, as well as between the tires. I'm thinking it's going to take some suspension work to raise your trailer significantly to go from a 14" tire to a 16" tire.

 

[J_Man]

I agree… it appears I could easily go to a 15-in wheel with the same lug-nut diameter and gain an increase in the load capacity of the tires.

Going from 14-to-16 would be a much more significant challenge and I’m not even convinced I need to go to a 15-inch wheel.


J_Man

 

[Hit Factor]

I put bigger wheels/tires on a TT some years ago, 14 to 16 IIRC. I ended up putting taller stabilizers on the TT. Using blocks is cheaper, but that's more items to carry, setup, and teardown.

 

[johnmyster]

As much as I'm an advocate of a quality LT over ST, your question is less about ST vs LT and more about finding a good quality option for your specific trailer. Disclaimer, I have Michelin Agilis CrossClimate 225/75r16C (120T) on our travel trailer, rated 3195 pounds and 107 mph, carrying ~2200 pounds each...they replaced GY-E 235/85r16.

Swapping axles to get to a 16" six lug seems silly.

If you can find a set of used 15" wheels in the right bolt pattern (5 lug?), it will affordably give you more tire options and more tire margin than 14" wheels. From there, clearance will dictate your options. You'll have many more ST options in 205/75r15 or 225/75r15.

How much load are you carrying per tire?

In yesteryear you might have had some 215/75r15 or 235/75r15 options with LR-C or LR-D load ratings. Options are slim in 2025. Not many pickups still running 15" tires. This is where a time machine would be handy.

In 2025, your best "LT" 15" options will actually be C-metric tires (euro van and caravan) - Continental Vanco 195/70r15C (104T) or Michelin Agilis CrossClimate 205/65r15C (102T) are two high quality examples with some load capacity in 15". Look for the C at the end of the designation which is the european Commercial designation, not load range C. Not many of the eurovan 15" models get imported into the US, so pickings are again, slim.

Carlisle, Transeagle, and Hercules have some 15" load range g ST options but those are not appropriate for your tiny rig.

 

[J_Man]

@johnmystrt >“Swapping axles to get to a 16" six lug seems silly.”

I agree completely.

15-in wheels with “ST” tires seems like a relatively easy, low-cost upgrade… and I’m 95% confident I have clearance for 15-inch wheels and tires.

(Aluminum wheels run ~$650, and replacement tire costs are close to zero-$ increase).

As for LT tires providing a smoother ride, how would I ever know?

Measurements would take me close to 100% confident but the variable I’m not sure about is compression / flex of the leaf-spring suspension —

How much clearance would I need between chassis (floor / belly of RV) and top of tire??? I do not know how to measure or calculate that clearance spec!

I doubt even an upgrade to 15-in is a reasonable value proposition, but I do tend to be a ‘belt-and-suspenders’ kind of guy.

I do not expect I’ll ever tow over rough ‘wash-board’ roads typical of the national forest areas where I used to hunt and fish.


J_Man

 

[Boots1950]

LT tires are for Light Trucks. ST tires are for Trailers. The compounds used in manufacturing is different. You should only use ST tires on the trailer because they are made for extended time parked. LT tires are not.

 

[Hoopy Frood]

LT tires are for Light Trucks. ST tires are for Trailers. The compounds used in manufacturing is different. You should only use ST tires on the trailer because they are made for extended time parked. LT tires are not.

Nonsense.

 

[johnmyster]

@johnmystrt >“Swapping axles to get to a 16" six lug seems silly.”

I agree completely.

15-in wheels with “ST” tires seems like a relatively easy, low-cost upgrade… and I’m 95% confident I have clearance for 15-inch wheels and tires.

(Aluminum wheels run ~$650, and replacement tire costs are close to zero-$ increase).

As for LT tires providing a smoother ride, how would I ever know?

Measurements would take me close to 100% confident but the variable I’m not sure about is compression / flex of the leaf-spring suspension —

How much clearance would I need between chassis (floor / belly of RV) and top of tire??? I do not know how to measure or calculate that clearance spec!

I doubt even an upgrade to 15-in is a reasonable value proposition, but I do tend to be a ‘belt-and-suspenders’ kind of guy.

I do not expect I’ll ever tow over rough ‘wash-board’ roads typical of the national forest areas where I used to hunt and fish.


J_Man

Run your hand around the tire to gauge clearance. Then put a jack under one axle and lift until the other tire comes off the ground. Thats full compression. Gauge clearance again.

Maybe you can borrow a spare from a friend, mount it and see. The rim only increases 1/2” radially. Tire size will have greater impact.

There are two types of people in the world. One thinks the “special” in ST means superior. The other doesn’t. Decide which one you are and then move on. I read the DOT testing requirements for LT and ST, then listened to people’s experiences with GY-E (which matched mine) and decided which I was.

 

[J_Man]

Your “full compression” explanation for the spring suspension is very helpful — thank you!


J_Man

 

[PeterInNH]

I’ve been watching a couple of threads about different tire brands failing on RVs, and I had a related question but to avoid high-jacking someone else’s post I’m asking this in a new thread.

I have almost no tire brand loyalty, and very limited experience with RV tires. Our 2025 GD 22MLE is relatively light weight, and came with GY Endurance ST205/75R14 tires.

We now have approximately 5,000 miles on our 22MLE with zero tire issues. I expect we won’t (or shouldn’t) need new tires for the next couple of years.

But, I’m starting to wonder what tire I should look for when the time comes to replace the OEM tires.

Are LTs a better solution to replace the STs?

I’m not thrilled to have what I think are ‘smallish’ (14-inch) tire/wheels, so I’m wondering if I should plan to buy 16-in LTs (new rims and maybe brake drum upgrades to accommodate the 6-lug wheels… which may mean new axels) - lots of $$$ and complexity.

Then, my sanity slowly returns and I remind myself that I’m having ZERO issues running the 14-in tires, and going bigger is a total waste of time and $$$.

So, back to initial question: LT vs. ST?

Advice and/or experience would be helpful and appreciated.


J_Man

Seems like a reasonable article:

What’s the difference between ST and LT tires (and why LT tires don’t belong on boat trailers)? - Venture Trailers

Boat trailers need ST tires—not LT truck tires. Learn the construction differences, why sidewall stiffness and load at pressure matter, and how the trailer duty cycle (constant load, axle scrub, heat/dunk cycles) makes LT tires a bad choice.

venturetrailers.com

tldr
Never put LT tires on a trailer

 

[Hoopy Frood]

Seems like a reasonable article:

What’s the difference between ST and LT tires (and why LT tires don’t belong on boat trailers)? - Venture Trailers

Boat trailers need ST tires—not LT truck tires. Learn the construction differences, why sidewall stiffness and load at pressure matter, and how the trailer duty cycle (constant load, axle scrub, heat/dunk cycles) makes LT tires a bad choice.

venturetrailers.com

tldr
Never put LT tires on a trailer

Sorry but I've read too many accounts of people putting LT tires on trailers with no ill affects. Which is more than you can say about people who put ST tires on trailers.

 

[18CrewDually]

Sorry but I've read too many accounts of people putting LT tires on trailers with no ill affects. Which is more than you can say about people who put ST tires on trailers.

I'm one of them. LTs on my last 5er in 2011 and sold it last year still with LTs. One tire got a nail once in TN and I plugged it. Never a blow out after wearing out 2 sets and installing a third set. From Maine to Fl to TN annually and everywhere in between over those years. Also run them on my 32' tandem dually 12k axle gooseneck. I regularly haul 26-30k lbs.
One thing people don't realize, there are trailer manufacturers that sell trailers with LTs. Cedar Creeks did, along with many others. Now that 17.5" commercial tires started being used not many use LTs but I did see a Winnie Minnie on a dealer lot with LTs from the factory.
So to say "you can't" or shouldn't, is wrong. Many do and never look back. Experience I have will never change my mind. Another food for thought for the nay sayers, my truck has LTs and the front axle tires see way more stresses cornering with 6k lbs daily and never had a blowout. Try that with STs. There's a reason STs say on them "For Trailer Use Only" and that is because they would never hold up on a steer axle of a vehicle.
So I said my story, I'm sticking to it and is all I got to say. Not here to argue.