Why Load Ratings Matter
Load ratings determine how much weight a tire can safely carry. For trucks and Jeeps that tow, haul, or carry heavy off-road gear, understanding load ratings is essential for safety and tire longevity.
Load Range Explained
Load range indicates a tire's maximum load capacity and is designated by letters. Here's what each means:
Common Load Ranges
- SL (Standard Load): For passenger vehicles; max 35 PSI
- XL (Extra Load): Higher capacity passenger tires; max 41 PSI
- C (6-ply equivalent): Light truck; max 50 PSI
- D (8-ply equivalent): Light truck; max 65 PSI
- E (10-ply equivalent): Heavy-duty truck; max 80 PSI
- F (12-ply equivalent): Commercial; max 95 PSI
Ply Rating vs. Actual Plies
Modern tires don't actually contain the number of plies their rating suggests. A "10-ply" E-rated tire might only have 2-3 actual plies, but they're made from stronger materials that provide equivalent strength to 10 old-style plies.
Load Index Numbers
The load index is a number (like 121) that corresponds to a specific weight capacity per tire. For example:
- 116: 2,756 lbs per tire
- 120: 3,086 lbs per tire
- 121: 3,197 lbs per tire
- 126: 3,748 lbs per tire
To find your vehicle's total capacity, multiply the per-tire rating by 4 (or 6 for dually trucks).
Matching Load Range to Your Needs
Daily Driving (No Heavy Loads)
For typical daily driving without heavy payloads or towing, Load Range C or even SL/XL tires may suffice. They offer a more comfortable ride and better fuel economy than heavier ratings.
Occasional Towing/Hauling
Load Range D provides a good balance for trucks that occasionally tow trailers or carry moderate payloads. The stiffer sidewalls handle extra weight while maintaining reasonable ride quality.
Heavy Towing and Work Trucks
Load Range E is the go-to for trucks that regularly tow heavy trailers or carry significant payloads. The higher pressure capacity and stiffer construction handle weight safely.
Off-Road Use
For serious off-roading, Load Range E tires offer benefits beyond weight capacity. The stiffer sidewalls resist punctures and provide better control when aired down on rocks.
Downsides of Higher Load Ratings
More isn't always better. Higher load range tires have tradeoffs:
- Harsher ride: Stiffer sidewalls transmit more road imperfections
- Heavier weight: Increases unsprung mass, affecting handling and MPG
- Higher cost: E-rated tires typically cost more than C-rated
- Overkill for light use: If you never haul heavy loads, you're just adding harshness
Calculating Your Needs
To determine the right load range:
- Find your vehicle's GVWR (Gross Vehicle Weight Rating)
- Divide by 4 to get per-tire requirement
- Add safety margin (10-15% recommended)
- Select a load index that meets or exceeds this number
Example Calculation
For a truck with 7,000 lb GVWR:
- Per tire: 7,000 ÷ 4 = 1,750 lbs
- With 15% margin: 1,750 × 1.15 = 2,012 lbs
- Load index 116 (2,756 lbs) would be appropriate
Pressure and Load Relationship
A tire's load capacity is only valid at its maximum rated pressure. Running lower pressures reduces capacity. This is why load range matters – higher ratings allow higher pressures and therefore higher capacity.
The Speed Rating Factor
Don't forget speed ratings when selecting tires. Many LT tires have lower speed ratings than passenger tires. Common ratings:
- Q: 99 mph
- R: 106 mph
- S: 112 mph
- T: 118 mph
Our Recommendations
- Light-duty trucks (daily use): Load Range C or D
- Half-ton trucks (occasional towing): Load Range D or E
- 3/4-ton and 1-ton trucks: Load Range E
- Dedicated off-road rigs: Load Range E for sidewall protection