Why Trailer Tires Fail Under Heavy Loads

[MikePhua]

The Hidden Stress Behind Trailer Tire Failures
Trailer tires often operate under extreme conditions—hauling heavy machinery, enduring long distances, and facing fluctuating temperatures. Despite their rugged appearance, these tires are vulnerable to a specific type of failure: sidewall delamination. This issue typically presents as a flap or blister where the sidewall meets the tread, sometimes forming a two-inch square rupture. While the tread may remain intact, the structural integrity of the tire is compromised, posing serious safety risks.
In one documented case, a gooseneck trailer equipped with dual 10,000 lb axles experienced multiple sidewall failures across different tires. The damage appeared on both sides of the trailer, ruling out alignment or axle-specific causes. The tires were not retreads, and the trailer had not exceeded moderate speeds. Yet the failures persisted, prompting a deeper investigation into contributing factors.
Overloading and Underinflation Are Silent Killers
One of the most common culprits is overloading. Many trailers rated for 14,000–15,000 lbs are routinely pushed to carry 18,000 lbs or more—especially when transporting dozers, backhoes, or skid steers. This overload stresses the tire carcass beyond its design limits, especially during cornering or braking.
Underinflation compounds the problem. A tire operating at 10–20% below its rated pressure generates excess heat due to increased flexing. This thermal buildup weakens the bond between the tread and sidewall, eventually causing separation. Operators often overlook inflation checks, assuming visual inspection is sufficient. However, a tire can appear full while still being dangerously underinflated.
Heat and Tire Construction Play a Critical Role
Heat is a tire’s worst enemy. On hot summer days, road surface temperatures can exceed 140°F (60°C). Combined with internal friction, this can push tire temperatures past 200°F (93°C). At these levels, rubber compounds begin to degrade, and steel belts may shift or warp.
Some trailer tires use sidewall materials that flex differently than the tread belts. This mismatch creates stress points, especially during high-speed travel or sharp turns. Inexpensive tires often lack the layered reinforcement found in premium brands, making them more susceptible to delamination.
LT Tires vs. ST Tires for Trailer Use
Many experienced haulers prefer LT (Light Truck) tires over ST (Special Trailer) tires. LT tires are built for dynamic loads and steering forces, offering better sidewall strength and heat resistance. ST tires, while designed for trailer applications, often prioritize cost over durability.
One operator reported replacing two brand-new 10-ply ST tires within weeks, despite never hauling more than 4,000 lbs or traveling beyond 50 miles. In contrast, his LT tires lasted significantly longer under similar conditions. This anecdote reflects a broader trend: LT tires may offer better real-world performance, especially for trailers used in mixed-duty cycles.
Wheel Size and Load Distribution Matter
Wheel diameter affects tire performance. Trailers equipped with 17.5" wheels tend to fare better than those with 15" or 16" wheels, due to improved load distribution and sidewall stiffness. However, even 17.5s are not immune to failure if overloaded or underinflated.
Some operators advocate for upgrading to 22.5" commercial-grade wheels, commonly found on semi-trailers. These tires are designed for sustained highway use and heavy loads, offering superior heat tolerance and tread life. While the conversion requires axle and hub modifications, the long-term benefits may justify the investment.
Terminology Clarification

• Sidewall Delamination: Separation of the tire’s sidewall from the tread, often caused by heat or structural stress
  
• LT Tire: Light Truck tire designed for dynamic loads and steering forces
  
• ST Tire: Special Trailer tire designed for static loads and straight-line towing
  
• Ply Rating: Indicates the tire’s load-carrying capacity; higher ply ratings mean stronger sidewalls
  
• Bead: The edge of the tire that sits on the wheel rim, anchoring the tire in place
  

Preventive Measures and Best Practices
To reduce the risk of tire failure:

• Use a temperature gun to monitor tire and hub temperatures during long hauls
  
• Check and adjust tire pressure before every trip, especially under heavy loads
  
• Avoid exceeding the trailer’s rated payload, even if the axles can handle more
  
• Rotate tires regularly and inspect for sidewall bulges or tread separation
  
• Consider upgrading to LT or commercial-grade tires for better durability
  

One Alberta-based hauler shared his routine: every few hours, he stops to check tire temperatures and pressure, using the break to hydrate and inspect the trailer. This habit has helped him avoid blowouts and extend tire life, even when hauling excavators across rugged terrain.
Final Thoughts
Trailer tire failure is rarely random—it’s the result of cumulative stress, heat, and design limitations. By understanding the mechanics behind sidewall delamination and adopting proactive maintenance habits, operators can prevent costly breakdowns and ensure safer hauls. Whether upgrading to LT tires or investing in larger wheels, the key is to respect the physics of load, heat, and motion. In the world of heavy hauling, tires are not just rubber—they’re the foundation of reliability.