Tuesday, August 9, 2022


Are “ST”-type tires required on trailers?

RV Tire Safety
with RV tire expert Roger Marble

“My 2012 Airstream Classic came with Goodyear Marathon ST225/75R15 LR-D tires. I would like to tell you how many original installed tires I have had blow out using the original and same size tires as replacements. I even replaced the LR-D’s with LR-E’s and still only get about 3,000 miles before blowouts. It is the damage caused by the blowouts that concerns me most. I am tired of fixing my trailer after blowouts.

“As I alluded to in my earlier message, I owned an Alpha 5th wheel that had 16” wheels as the original size. After 5 blowouts in one 6,000 mile trip I replaced the tires with Michelin LT235/75R16 XPS RIB (All Steel) tires. These tires are made with steel sidewalls. Many thousands of miles later I traded the trailer for my present Airstream without any more blowouts on my Alpha.

“I have another question that does not appear to have a good answer. If trailer tires are so good and must be installed on a trailer when truck tires wear so much better, what is the rationale for requiring the STs on a trailer? My truck, a 2002 GMC Duallie, uses LT tires and I can not wear them out, not blow them out, before I feel it is safe to replace them (7 years). I am running LR-E LT types on my truck.

“I am sorry to say that I do not agree with the idea that ST tires for trailers is the safest and best option.”

I have never seen any “requirement” that trailers run ST-type tires. However, ST-type tires can only be installed on trailers, so that might be the “requirement” you are thinking of.

The selection of tires to use on any vehicle is up to the RV company. As far as I can see, they select tires based only on load capacity, physical size and cost. I don’t know what the RV company actually pays for ST tires but it is probably less than an LT of equivalent load capacity.

If your only concern was for lower cost when comparing two tires of equal load capacity and the ST tire was easier to fit (it was smaller and did not require you make larger wheel wells), why would you select the higher-cost tire? If you don’t offer a meaningful warranty, you do not face the expense of warranty costs if there is a tire failure so what is the incentive for the RV company to spend more?

Read more from Roger Marble on his blog at RVtiresafety.net.



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John T
3 years ago

Most people don’t get any blowouts with their ST tires, so if you’re getting multiple blowouts, you’re either overloading, overspeeding or under-inflating.

Richard D. Smith
3 years ago

My 30 foot cargo trailer which I purchased from the original owner came with 235/85R/16 LT tires on them. After multiple sidewall failures I finally spent the money to install Goodyear Unisteel G614 Radial Trailer Tires. There is no better trailer tire than these. They are built like big rig trailer tires and can be re-grooved also. Stiff sidewalls is what you want and these definitely fit the criteria. I won’t have anything else on my trailers except for the Goodyear G614 Tires. You are wasting your time AND money with LT tires.


Roger Marble
3 years ago

Richard, You didn’t mention the Load Range and inflation pressure of the LT type tires. The Unisteel are LR-G rated for 110 psi and significantly greater load capacity than the LT tires you had previously. I am curious about the type tire and recommended inflation shown on your trailer certification label.

John Rakoci
3 years ago

Actually, the Sailun S637 is also a G rated tire with higher load capacities, a better reputation, and at half the cost.

3 years ago

It is all about the ‘Benjamins.’ All decisions going into the design and manufacture of everything is about the bottom line of the company producing the product. At what price point do they need to be to remain competitive and return money to the firm and it’s investors?

Dump the ST tires and get ones that work for your situation.

Bob p
3 years ago

My last 5th wheel was equipped with LT23585R16 tires (the same as my GMC dually). We put 15k miles on that trailer and never had a problem. The tires still looked good and had 65% tread left when we sold it.

Roger Marble
3 years ago
Reply to  Bob p

Glad to hear you haven’t had tire problems. What is your actual load on each tire? Tire Inflation?

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