What is the Difference Between a Trailer Tire and a Regular Tire?

Contrary to popular belief, not all tires are created equal. This is especially true with trailer tires, which differ significantly from their automotive counterparts.

Exactly how different trailer tires are from regular tires is a debate that hasn’t yet been settled; internet forums remain ablaze with wildly different opinions on the issue. But talk to the tire manufacturers you’ll get a more unilateral answer: they all attest that there are significant differences in the construction of passenger-car and trailer tires.

To better understand the differences between these two tire designs, it helps to first understand the various types of tires currently on the market.

Tire Classifications: P, LT, and ST

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If you’ve ever tried to decipher a tire sidewall, you’re probably familiar with the various classifications manufacturers use to identify the qualities of particular tires. Z-rated tires, for instance, indicate the tire can safely reach speeds of at least 149 mph; a load-bearing rating (which identifies how much weight a single tire can support) such as 102S translates to a maximum load capacity of 1,874 pounds.¹

Likewise, tire manufacturers use an agreed-upon classification system to separate tires into specific families based on the intended application. A light-duty tire for a sedan or small crossover carries the P classification, for instance. The letter P signifies to those in the know that the tire has been designed for the typical usage expected of a light-duty passenger vehicle.

Light Truck (LT) tires are intended for three-quarter or one-ton pickup trucks – that’s the heavy-duty full-size pickup trucks from Ford, Ram, GMC, and Chevrolet. These trucks can haul and tow substantial weight – and LT tires must be capable of supporting such prodigious ability.

Special Trailer (ST) tires are tires that have been specially designed for trailers, including fifth-wheels, boat trailers, campers, and so on. Just as LT tires are built to withstand the capability of full-size pickup trucks, ST tires must be built to withstand the forces enacted on the typical trailer.

Are All Tire Types Interchangeable?

Generally no.²

Tire types are built for specific applications. The qualities most important to P tires include gas mileage and ride comfort, but LT tires are willing to sacrifice both of these metrics in order to meet the towing and payload expectations of owners. Trailer tires are their own unique specimens that would be downright dangerous if installed on a car.

That said, LT tires can be interchangeable with P tires on light-duty pickup trucks – for those who do frequent towing or operate their truck in an extreme environment, the characteristics of the LT tire would be more appropriate than the street-friendly P tires that most light-duty trucks come with from the factory.

Things get murky when you begin to consider using LT tires on a trailer as opposed to ST tires, a topic that has been the focus of many a debate. To understand why, let’s look at both tire types in more detail.

LT Tires

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As we noted above, LT tires are designed for heavy-duty trucks such as the Ford F-250 and Ram 2500. These are traditional radial tires that – apart from their sheer size – don’t look much different than the P tire used on passenger cars and trucks.

Behind the appearance of these tires is some serious engineering, however. LT tires benefit from a strong sidewall thanks to the use of additional material within the tire. The tread is also thicker than both P tires and ST tires. To handle heavy loads, LT tires can withstand tire pressure much higher than ordinary P tires – sometimes as much as 70 or 80 psi.

Their heavy-duty construction also enables LT tires to have a higher load-bearing capacity than P tires, though this comes at the cost of ride quality. Nonetheless, the smoothness of the ride does remain a relevant factor in the design of LT tires.

Because LT tires are intended first and foremost for trucks, not trailers, these tires are designed with accelerating, steering, and braking in mind. They must be able to handle an influx of power from the drivetrain and the stresses inflicted by the steering system. These tires also must be able to handle all ranges of speeds and environments, from triple digits on the highway – not recommended, mind you – to muddy, rock-strewn trails.

ST Tires

Trailer tires are made with only two things in mind: bearing the weight of the trailer and following the tow vehicle. Other functions such as steering and acceleration are irrelevant, as there is no separate components directly driving or steering the trailer axles. Even ride quality isn’t a factor, as passengers should not be riding in a trailer as it is being towed.

Because of their specialized nature, trailer tires are built to significantly different specifications than LT or P tires. You can see this at a glance: compared to car tires, ST tires are taller and much narrower. Their tread design is also far more simplistic than some of the complex patterns found on automotive tires.

There are some invisible differences as well that are no less significant. Sidewall stiffness, for one – trailer tires are much less pliant than automotive tires. This reduces trailer sway and results in very strong load-bearing capacities, which is important if your trailer weighs 10,000, 20,000, or even 30,000 pounds fully loaded. If you don’t want a blowout, you need tires up to the challenge.

The stiff sidewall necessitates high tire pressure, with some ST tires calling for as high as 110 psi. Again, ride quality isn’t the concern here – it’s the load-bearing capacity that is paramount. Trailer tire manufacturers put out inflation charts – such as this one by Maxxis – to help owners determine proper inflation rates for their setup.

Notably, ST tires have a top speed of 65 mph. Any faster and the tire won’t be able to properly dissipate heat, which can lead to overheating and ultimately a blowout.

Trailer tires aren’t much good at steering, are ignorant of ride quality, and are allergic to speed. But they dutifully follow the tow vehicle and provide superior trailer stability at highway speeds.

Can I use LT Tires on my Trailer?

You can, but we wouldn’t recommend it. In their efforts to be excellent tires for heavy-duty trucks, they don’t incorporate any of the construction techniques that make ST tires so ideal for trailering.³

The lack of appropriate sidewall stiffness is the biggest concern with LT tires on a trailer; their additional pliancy invites more trailer sway, which could lead to potentially hazardous situations on the highway.

The tread design of LT tires could also impact trailer behavior. Unlike ST tires, which use a simple, straight-cut tread design that is happy to follow the lead tow vehicle, LT tires incorporate a more complex tread that may be more prone to wandering on the highway.

Load-bearing capacity can’t be overlooked either. LT tires take into consideration the weight of a truck frame and payload; ST tires are built with trailer frames and cargo in mind. On heavier trailers, in particular, the higher load capacity of ST tires is critical for proper trailering safety. Exceeding the load capacity of a trailer tire is an invitation to a tire blowout.

Parting Thoughts

Differences in construction, design, and material distinguish LT and ST tires. LT tires are designed for a wide range of circumstances, from towing heavy loads to cutting through trail. They must endure the stresses of every automotive component that directly drives, steers, and stops the vehicle. Not among their qualifications is trailer tire stand-in.

ST tires exist because trailers of any stripe have specific requirements for their tires. The most important considerations with towing – supporting trailer weight, following the tow vehicles, reducing trailer sway – are much different than the requirements of automotive tires. ST tires are built with those requirements in mind. If you’re looking into vehicle and trailer maintenance, though, you might also want to look into how long trailer tires last and whether you should balance your trailer tires.

If you’ve been thinking of putting LT tires on your trailer, we’d advise against it. The qualities of a good trailer tire are expressly designed with your trailering needs in mind. You might have to keep it under 65 mph on the interstate, but you’ll ultimately have a safer journey if you put the right tires to put on your trailer.

Article Sources

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