Guide to Trailer Tires
By Midwest Traction on May 8, 2018
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Trailer Tire Articles
When hauling heavy loads, it’s important to ensure that your equipment is in the best condition. Don’t overlook your tires. You’ll want to consider durability, performance in varying road conditions, low noise, ride comfort, and traction on wet surfaces.
ST vs LT: Can I use them interchangeably?
ST (Special Trailer) tires are designed to carry higher loads than passenger designated tires. While they’re not speed rated, it’s recommended to not exceed speeds of 65 mph, as this increases the risk of blowing a tire. ST tires are made of a harder rubber, with sidewalls designed to keep the tire centered, preventing it from rolling under the rim or buckling during tight turns. They use different steel belts, plies and beads with thicker cores and a wider wire to boost their strength and durability. Narrower treads with shallow depths reduce rolling resistance and tread squirm.
LT (Light Truck) tires can sometimes be used interchangeably for ST tires, though our recommendation is to always use ST to ensure safety and performance. LT tires offer more flexibility which isn’t ideal when you’re towing larger loads. They’re designated for passenger use, so their load capacity will be lower than ST tires.
Radial or Bias Ply?
Being clear about the weight of your load and how far/fast you intend to haul your trailer is vital for choosing which construction will be best for you.
Radial
For great distances at higher speeds, radial is ideal. They’re designed to resist heat build-up, have a longer tread life, and handle better on the road. They’re more expensive than bias ply tires and don’t perform well on rough roads, but they offer a smoother ride.
Best for: Highway use, long trips, and high speeds. If you plan to travel great distances or like to move fast, radial tires are best.
Bias
Bias tires aren’t meant to be driven at high speeds or carry exceptionally heavy loads because they are prone to heat buildup. They’re easier to repair and good for shorter distances, but wear out faster. They feature a more rugged design for off-road use and are typically less expensive than their radial counterparts.
Regardless of construction, it is important to examine your tires before you take long trips. Look for bulging, wear, baldness, and uneven tread. All of these affect handling, especially in wet conditions.
Load Capacity
It is important to consider the weight of your empty trailer versus the weight it will have when towing. This will greatly affect the tires you purchase. The combined capacity of your tires should meet or exceed the gross vehicle weight of your towing axle. The recommendation is that your tire capacity exceeds the loaded trailer weight by 20%.
When you’re towing items, like a boat, the manufacturer likely lists the weight of the vehicle, but ensure you account for additional items, like the battery, fuel, water, accessories, etc.
For loading: Rollers will make your job simpler. Check the warranty, as rollers can dimple boats and jet skis, which will void your manufacturer coverage. Trailer bunks are a good alternative that provides more support for the hull.
Inflation
Not only is proper air pressure important for fuel economy, but it improves your ride, tracking, longevity, and safety.
Underinflated tires result in excessive flexing, which builds heat that damages the inner liner, the casing, and the outer sidewall. Tires running at less than 80% of their recommended pressure should be inspected for damaged and replaced immediately. Overinflated tires result in uneven wear which increases the likelihood of blowouts. If you notice uneven wear but your PSI is set to manufacturer recommendations, do some vehicle inspection. It’s possible your alignment and tires need to be balanced.
Best practice: check your trailer tires every two weeks to every month, but if you’re traveling check:
- Before any long trips
- Every morning for multiple day trips
- Before leaving and after returning for single day trips
- Measure when tires are cold
TPMS
A useful tool for monitoring tire pressure is a Tire Pressure Monitoring System (TPMS). Blowouts often occur because of a slow leak that drops tire pressure while the vehicle is moving, which heats the tire up until it bursts.
Every time tires are replaced, low-pressure valves should be replaced. High-pressure tires require special valves, and dual tires have to have accessible valves for filling and checking. Special hoses are available to extend the reach to check them, but they’re subject to leaks. Extended valve stems are a good alternative. Regardless of valve size, TPMS is a good investment.
Storage
The nature of trailer tires is that they’re often not used year-round. You’re either camping, boating, or towing things.
Before You Store
Clean the tires with soap and water. Look for a location that doesn’t involve direct sunlight. as UV rays break down rubber over time and can lead to cracking (dry rot). You may purchase tire covers for this, but avoid sidewall dressings containing petroleum distillates. They deteriorate rubber. Inflate the tires to recommended operating pressure plus 25% (do not exceed rim manufacturer’s inflation capacity).
During Storage
Move the tires periodically, at least once every 3 months to prevent ozone cracking in the tire bulge region. Flat spotting can happen when tires sit too long, resulting in straining of the sidewall and tread deflection. Storage surfaces should be firm, clean, well-drained and reasonably level.
If you’re storing indoors, make sure there are not ozone-generating devices near the tires, such as electric motors to prevent dry rot.
Trailer Tires to Check Out
Looking for a few solid trailer tire recommendations? We've got 3! Or check out our entire trailer tire selection here.