Truck tires typically come in two load ratings: G and H.
The G-rated trailer tires are specially designed for handling large RVs and trailers. They have a higher weight tire capacity than other tires and can take a variety of terrains. They can handle about 4400 lbs each. Each model tire is a little different.
An H load range tire can handle much more, about 6700 lbs each. Infographic:
Tires are rated by how much weight they can carry, and have a ply rating.
- H rated tires have 16 plies and can carry more, about 1k lbs more per tire compared to a G, a good choice for RV. Capacity 6700 lbs.
- G Load Range has a ply rating of 14, good for RV. Capacity 4400 lbs.
- F Load Range tires have 12 ply rating, and 3600 lbs capacity.
- E has 10 ply, good choice for F250 or F350 truck, 3000 lbs capacity.
- D has 8 ply, capacity of 2200 lbs.
- C has 6 ply, good for F150 pickup.
If you overload tires they will wear out faster. If you get tires that are overly strong you will be weighted down because they are heavy. The load range is printed on the side of every tire.
Dangers of overloaded tires
Here are some technical aspects to consider when discussing the consequences of overloading tires:
- Tire structural integrity: Overloading increases the stress on tire components, such as the ply, belts, and sidewalls. The excess weight can lead to deformation, fatigue, and potential failure of the tire’s internal structure.
- Heat generation and dissipation: The increased flexing of an overloaded tire causes greater heat generation. This heat buildup can exceed the tire’s ability to dissipate it, leading to accelerated deterioration of rubber compounds, adhesives, and other materials within the tire. The excess heat can also cause the tire’s steel belts to separate or weaken, further compromising the tire’s structural integrity.
- Tire pressure and contact patch: Overloaded tires can cause changes in the tire’s contact patch, which is the area of the tire in contact with the road. The overloaded tire may deform, resulting in a larger contact patch that generates more friction and heat. Additionally, an overloaded tire can experience uneven pressure distribution, leading to uneven tire wear and reduced traction.
- Vehicle dynamics: The additional weight on overloaded tires can significantly affect a vehicle’s dynamics, including its handling, braking, and stability. Increased stopping distances, reduced cornering ability, and diminished vehicle stability can all result from overloading tires.
- Suspension and drivetrain components: Overloading tires can also put additional stress on the vehicle’s suspension, including the springs, shocks, and struts. This stress can lead to premature wear and potential failure of these components. Similarly, the extra weight can strain the vehicle’s drivetrain components, such as the transmission and axles.
- Tire load index and inflation pressure: The tire load index is a numerical code that indicates the maximum load a tire can carry at a specified inflation pressure. Overloading a tire beyond its load index can result in structural damage, reduced performance, and increased risk of failure. Maintaining the proper inflation pressure is crucial to supporting the tire’s load-carrying capacity and ensuring optimal performance.
Load ratings
- Gross Vehicle Weight Rating (GVWR): This is the maximum total weight a vehicle can safely carry, including the RV’s own weight, passengers, cargo, fuel, water, and propane. For example, a Class C motorhome might have a GVWR of 14,500 pounds, meaning the total combined weight of everything in and on the vehicle should not exceed 14,500 pounds.
- Gross Axle Weight Rating (GAWR): This is the maximum weight that can be placed on a single axle (front or rear) of the vehicle. For example, a travel trailer may have a GAWR of 3,500 pounds for each axle. This means that each axle of the trailer should not carry more than 3,500 pounds, including the weight of the trailer and the cargo.
- Cargo Carrying Capacity (CCC): This is the maximum amount of weight that can be added to the RV in the form of passengers, personal belongings, food, and other supplies. The CCC is calculated by subtracting the vehicle’s Unloaded Vehicle Weight (UVW) from its GVWR. For example, if an RV has a GVWR of 11,000 pounds and a UVW of 8,000 pounds, its CCC would be 3,000 pounds.
Tire selection
- Speed Rating: The speed rating is a letter code that indicates the maximum speed the tire can sustain for an extended period when properly inflated and under its rated load capacity. In the previous example (225/45R17 94V), the speed rating is ‘V,’ which corresponds to a maximum speed of 149 mph (240 km/h).
- Treadwear, Traction, and Temperature (UTQG) Ratings: The Uniform Tire Quality Grading (UTQG) system is used to provide consumers with information regarding a tire’s relative treadwear, traction, and temperature capabilities.
- Treadwear: This is a numerical rating that indicates the tire’s relative wear rate compared to a reference tire with a rating of 100. A higher number means the tire should have a longer tread life.
- Traction: This rating (AA, A, B, or C) represents the tire’s ability to stop on wet pavement under controlled testing conditions. AA is the highest rating, while C is the lowest.
- Temperature: This rating (A, B, or C) indicates the tire’s resistance to heat generation and its ability to dissipate heat when tested under controlled conditions. A is the highest rating, while C is the minimum performance required by law.
More about tires: https://www.worktruckonline.com/329088/how-to-understand-truck-tires-load-ratings-sizes-more
