Trailer Tires: Pick the BEST Ones!
Ever think about the unsung heroes carrying your precious cargo? We’re talking about trailer tires! Often overlooked, these crucial components are the difference between a smooth, safe journey and a roadside nightmare. From hauling boats and RVs to utility trailers and car carriers, the right set of trailer tires ensures stability, safety, and prevents costly breakdowns.
Don’t just grab any old tire; understanding the unique demands placed on trailer tires is key to making an informed decision. This comprehensive guide will equip you with everything you need to know to choose, maintain, and maximize the lifespan of your trailer’s rubber.
Why Trailer Tires Are Different (and Why it Matters!)
Unlike passenger car tires, trailer tires are specifically engineered to handle constant heavy loads, withstand prolonged periods of inactivity, and resist sidewall flex. They are not designed for traction or comfort in the same way car tires are.
ST vs. LT: Know the Difference
When you’re shopping for trailer tires, you’ll primarily encounter two designations:
ST (Special Trailer): These are specifically designed for trailers. Construction: Stiffer sidewalls reduce sway and are built to handle high pressures. Purpose: Engineered for carrying heavy loads over long distances. Load Capacity: Offer higher load capacities for their size compared to LT tires. Recommendation: Always the preferred choice for most trailers. LT (Light Truck): While designed for trucks, they are sometimes (incorrectly) used on trailers. Construction: More flexible sidewalls designed for traction and ride comfort on a vehicle’s drive axle. Purpose: Not ideal for the continuous, static heavy loads and sidewall scrubbing experienced by trailers. Risk: Can lead to excessive heat buildup and premature failure when used on trailers.
Construction: Radial vs. Bias-Ply
You’ll also encounter different construction types for trailer tires:
Radial Trailer Tires: Construction: Plies run radially across the tire, similar to passenger car tires. Benefits: Run cooler, offer longer tread life, and provide a smoother ride. Modern Choice: The most common and recommended type for most modern trailers due to their superior performance and durability. Bias-Ply Trailer Tires: Construction: Plies run diagonally from bead to bead. Benefits: Often have stronger sidewalls, offering more resistance to punctures. Use Case: Sometimes found on older or very heavy-duty utility trailers where low speed and maximum sidewall strength are priorities. Drawbacks: Tend to run hotter, have a shorter tread life, and can cause more trailer sway.
Key Factors When Choosing Your Trailer Tires
Making the right choice involves more than just picking the first option. Here’s what to consider:
Load Capacity: Don't Overlook the Weight
This is perhaps the most critical factor. Your trailer tires must be able to support the Gross Vehicle Weight Rating (GVWR) of your trailer.
Check GVWR: Find your trailer’s GVWR on its VIN sticker or owner’s manual. Divide by Tires: For tandem axle trailers, divide the GVWR by the number of tires (e.g., 4) to find the minimum load capacity per tire. Always aim for a buffer. Load Range: Trailer tires have a “Load Range” (e.g., C, D, E) indicating their ply rating and maximum load at a specific inflation pressure. Always match or exceed your trailer’s requirements. Safety First: Overloading your tires is a recipe for disaster and can lead to dangerous blowouts.
Size Matters: Get the Perfect Fit
Always replace trailer tires with the exact size specified by the trailer manufacturer or the size currently on your trailer.
Read the Sidewall: The size (e.g., ST205/75R15) is clearly marked on the tire’s sidewall. Match Wheel Size: Ensure the tire diameter matches your wheel diameter (e.g., 15 inches). Never Mix Sizes: Especially on tandem axles, always use identical tire sizes and types.
Speed Rating: Stay Within Limits
Trailer tires typically have lower speed ratings than passenger car tires.
Common Rating: Most ST trailer tires have an M speed rating, which means they are safe up to 81 mph (130 km/h). Caution: Exceeding the speed rating can cause excessive heat buildup, leading to tire failure. Always adhere to the tire’s specified speed limit, especially when heavily loaded.
Tread Pattern: Specific Needs
While trailer tires don’t need aggressive tread for traction, there are differences:
Highway Tread: Most common, designed for stability and reduced rolling resistance on paved roads. All-Terrain/Off-Road: For utility or boat trailers frequently used on gravel, dirt, or boat ramps, a slightly more aggressive tread can offer better grip.
Age: The Silent Killer
Unlike car tires that wear out, trailer tires often “time out” due to UV exposure, oxidation, and simply sitting still.
Check DOT Code: Locate the four-digit DOT code on the sidew (e.g., “1522” means the 15th week of 2022). Replacement Guideline: Most experts recommend replacing trailer tires every 3-5 years, regardless of how much tread they have left. Old tires are prone to dry rot and sidewall cracking, which can lead to sudden failure.
Maximizing the Life of Your Trailer Tires
Investing in good trailer tires is only half the battle. Proper maintenance is crucial for safety and longevity.
Proper Inflation: Your #1 Priority
Under-inflation is the leading cause of trailer tire failure.
Max PSI (Cold): Always inflate your trailer tires to the maximum PSI indicated on the tire’s sidewall (NOT the vehicle placard). Check Cold: Measure tire pressure when the tires are cold (before driving) for the most accurate reading. Regular Checks: Check pressure before every trip, even short ones.
Regular Inspections: Catch Problems Early
Make a habit of inspecting your trailer tires before and after each use.
Visual Check: Look for cracks, bulges, punctures, missing valve caps, and uneven wear patterns. Tread Depth: Ensure adequate tread depth. Lug Nuts: Double-check that all lug nuts are tight.
Storage Smartly: Protect from the Elements
When your trailer isn’t in use, take steps to protect its tires.
UV Protection: Use tire covers to shield them from harmful UV rays, which accelerate aging and cracking. Lift if Possible: For long-term storage, consider jacking up the trailer to take weight off the tires, or at least move the trailer occasionally to prevent flat spots. Cool, Dry Place: Store your trailer in a cool, dry place if possible.
Balancing and Alignment: Smooth Rolling
While often overlooked for trailers, balancing and alignment are still important.
Balancing: Properly balanced trailer tires reduce vibration, leading to more even wear and a smoother tow. Alignment: If your trailer has adjustable axles, proper alignment prevents scrubbing and premature wear.
When to Replace Your Trailer Tires
Don’t wait until it’s too late! Replace your trailer tires if you observe any of the following:
Visible Damage: Cracks in the sidewall or tread, bulges, separation, or significant punctures. Tread Wear: Tread depth is below 2/32 of an inch (use a penny test: if Lincoln’s head is fully visible, it’s time). Age: They are 5 years old or older, regardless of their appearance or tread. Before a Big Trip: If your tires are nearing their end-of-life, replace them before embarking on a long journey.
Investing in high-quality trailer tires and maintaining them properly is a small price to pay for peace of mind and safe travels. Don’t compromise on safety – pick the BEST ones for your trailer and enjoy the open road!