11 hours ago
Upgrading Tire Load Ratings for Safety and Longevity
When hauling heavy equipment like large backhoes or skid steers on triple-axle trailers, tire selection becomes a critical safety and performance factor. A common configuration includes three 7,000 lb axles, totaling 21,000 lbs of capacity. However, when loaded to near maximum—such as 20,740 lbs on the axles and 3,020 lbs on the tongue—the standard E-rated tires (235/85R16, rated at 3,042 lbs each) are pushed beyond their limits. This scenario demands a tire upgrade to maintain safety margins and avoid blowouts or premature wear.
Terminology Clarification
Two upgrade paths are commonly considered:
For trailers with 1/2" studs, fitting 17.5" wheels designed for 5/8" studs requires creative solutions. One proven method involves using custom shims to center the wheel and sourcing flat-face lug nuts from racing suppliers. Some operators reverse 1" lug nuts designed for stock cars to achieve proper seating. While unconventional, this setup has proven durable over thousands of miles.
Benefits of Upgrading to 17.5" Tires
Before switching to larger tires, verify that axle spacing allows for proper clearance. Fortunately, 215/75R17.5 tires are slightly smaller in diameter than 235/85R16s, reducing the risk of rubbing between axles. Still, measure carefully and account for suspension travel.
Field Experience and Anecdotes
Operators who’ve made the switch to 17.5" tires consistently report smoother towing and longer tire life. One contractor noted that after four years of use, his first set of 17.5s had worn evenly and outlasted multiple sets of 16" E-rated tires. Another shared that the upgrade was “the best thing I ever did to the trailer,” despite the need for custom lug nut solutions.
Conclusion
For heavy triple-axle trailers operating near capacity, upgrading from E-rated 16" tires to G-rated or 17.5" commercial tires is a smart investment. While 17.5" wheels may require fitment adjustments, the benefits in safety, durability, and towing performance are substantial. Whether hauling across town or across states, the right tires make all the difference.
When hauling heavy equipment like large backhoes or skid steers on triple-axle trailers, tire selection becomes a critical safety and performance factor. A common configuration includes three 7,000 lb axles, totaling 21,000 lbs of capacity. However, when loaded to near maximum—such as 20,740 lbs on the axles and 3,020 lbs on the tongue—the standard E-rated tires (235/85R16, rated at 3,042 lbs each) are pushed beyond their limits. This scenario demands a tire upgrade to maintain safety margins and avoid blowouts or premature wear.
Terminology Clarification
- Load Rating: The maximum weight a tire can safely carry at its rated pressure.
- E-Rated Tire: Typically rated for 3,042 lbs at 80 psi.
- G-Rated Tire: Rated around 3,900 lbs at 110 psi, offering a significant upgrade.
- 17.5" Commercial Tire: Often rated above 4,800 lbs, designed for high-load trailers and commercial use.
- Lug Nut Shoulder Fitment: Refers to the interface between the wheel and lug nut, which must match stud size and wheel design.
Two upgrade paths are commonly considered:
- 235/85R16 G-Rated Tires: These offer a direct swap with higher load capacity. They fit existing 16" wheels and increase safety margins without requiring new rims.
- 215/75R17.5 Commercial Tires: These provide even greater load capacity (up to 4,805 lbs per tire) and are designed for 8,000 lb axles. They require new 17.5" wheels, often with 5/8" stud holes, which may not match 7,000 lb axle hardware.
For trailers with 1/2" studs, fitting 17.5" wheels designed for 5/8" studs requires creative solutions. One proven method involves using custom shims to center the wheel and sourcing flat-face lug nuts from racing suppliers. Some operators reverse 1" lug nuts designed for stock cars to achieve proper seating. While unconventional, this setup has proven durable over thousands of miles.
Benefits of Upgrading to 17.5" Tires
- Improved Towing Stability: Larger tires with higher ply ratings reduce sway and improve tracking.
- Extended Tire Life: Commercial-grade tires are built for long-haul durability and resist heat buildup.
- Reduced Blowout Risk: Higher load ratings provide a buffer against overload and uneven weight distribution.
- Better Heat Dissipation: Thicker sidewalls and steel belts handle sustained highway speeds more effectively.
Before switching to larger tires, verify that axle spacing allows for proper clearance. Fortunately, 215/75R17.5 tires are slightly smaller in diameter than 235/85R16s, reducing the risk of rubbing between axles. Still, measure carefully and account for suspension travel.
Field Experience and Anecdotes
Operators who’ve made the switch to 17.5" tires consistently report smoother towing and longer tire life. One contractor noted that after four years of use, his first set of 17.5s had worn evenly and outlasted multiple sets of 16" E-rated tires. Another shared that the upgrade was “the best thing I ever did to the trailer,” despite the need for custom lug nut solutions.
Conclusion
For heavy triple-axle trailers operating near capacity, upgrading from E-rated 16" tires to G-rated or 17.5" commercial tires is a smart investment. While 17.5" wheels may require fitment adjustments, the benefits in safety, durability, and towing performance are substantial. Whether hauling across town or across states, the right tires make all the difference.
