Lorry Tire Size Calculator
Here’s a comprehensive table summarizing all you need to know about lorry (truck) tire sizes:
| Component | Description | Example |
|---|---|---|
| Tire Type | P (Passenger), LT (Light Truck), or no letter (Metric) | LT or 295/ |
| Width | Tire width in millimeters | 295 |
| Aspect Ratio | Height of sidewall as a percentage of width | 80 |
| Construction | R (Radial) or D (Diagonal) | R |
| Rim Diameter | Diameter of the wheel rim in inches | 22.5 |
| Load Index | Maximum weight capacity (single/dual) | 156/150 |
| Speed Rating | Maximum speed capability | L |
Understanding Lorry Tire Size Components
Tire Type
- P: Passenger vehicles or light-duty trucks
- LT: Light trucks, typically for 3/4 and one-ton pickups
- No letter: Euro-Metric, usually for passenger vehicles
Width
The width of the tire in millimeters, measured from sidewall to sidewall1.Aspect Ratio
The height of the tire’s sidewall as a percentage of its width. A lower aspect ratio indicates a lower profile tire1.Construction
- R: Radial construction (most common)
- D: Diagonal or bias-ply construction (older type)
Rim Diameter
The diameter of the wheel rim in inches1.Load Index
Indicates the maximum weight the tire can support when properly inflated. For truck tires, often shown as two numbers for single/dual wheel configurations3.Speed Rating
Denotes the maximum speed capability of the tire. Common ratings for trucks include:
- L: 75 mph (120 km/h)
- M: 81 mph (130 km/h)
- N: 87 mph (140 km/h)5
Additional Considerations
Load Range
Indicated by letters (C, D, E, etc.), it represents the tire’s ply rating and load capacity. For work trucks, common ranges are C, D, and E5.Tread Patterns
- Directional: Designed to roll in one direction
- Symmetrical: Same pattern across the tire
- Asymmetrical: Different patterns for dry and wet traction
- Directional/Asymmetrical: Combines features of both4
Axle Position
- Steer: Front tires for steering control
- Drive: Middle tires connected to the engine
- Trailer: Rear tires for trailer support6
Understanding these components is crucial for selecting the right tires for your lorry, ensuring optimal performance, safety, and longevity