Understanding the information printed on a 4×4 tyre sidewall is essential when selecting the right tyres for off-road driving. These markings provide details about the tyre’s dimensions, construction, load capacity, speed rating, and manufacturing standards. Whether you’re replacing stock tyres or upgrading for overlanding, interpreting these figures correctly helps ensure your vehicle remains safe, compliant, and suited to the terrain.
Tyre Size ExplainedMost 4×4 tyres display a size in the format: 265/75R16. This code refers to:
- 265 – The tyre width in millimetres, measured across the tread.
- 75 – The aspect ratio, expressed as a percentage of the width. In this case, the sidewall height is 75% of 265mm.
- R – Indicates radial construction, which is standard for modern tyres.
- 16 – The wheel diameter in inches (rim size).
Some off-road tyres use imperial sizing, such as 31×10.5R15. In this format:
- 31 – Overall tyre diameter in inches.
- 10.5 – Tyre width in inches.
- 15 – Rim diameter in inches.
Load Index and Speed Rating
Next to the tyre size, you’ll often see a code like 113S. This refers to:
- 113 – The load index. This corresponds to a maximum load rating, with 113 representing 1,150 kg per tyre.
- S – The speed rating. ‘S’ is rated up to 180 km/h. Other common ratings include Q (160 km/h), T (190 km/h), and H (210 km/h).
Choosing the correct load index is important, especially for overlanding setups where vehicles often operate close to their maximum weight. Similarly, while speed ratings may seem secondary for off-road use, exceeding them—particularly on-road—can result in tyre failure.
Related: Beginner’s Guide to Buying a Used 4×4: What to Look Out For
Other Common Markings
- LT – Stands for “Light Truck”. Indicates a tyre with reinforced sidewalls and a stronger carcass, designed for heavier loads and rough conditions.
- M+S – Mud and Snow. Suggests better performance in soft or slippery terrain, though it does not imply specialist off-road capability.
- 3PMSF (Three-Peak Mountain Snowflake) – A certified symbol indicating the tyre meets winter traction standards. Mostly found on all-terrain tyres with snow capability.
- DOT Code – A compliance code issued by the U.S. Department of Transportation. The last four digits represent the manufacturing date (e.g. 4523 = week 45 of 2023).
Choosing the Right Tyre for Off-Road Use
Tyre size influences a range of factors, including ground clearance, gearing, fuel consumption and ride quality. Larger tyres can improve off-road capability but may affect drivetrain performance or cause rubbing if the vehicle is not properly modified.
All-terrain (A/T) and mud-terrain (M/T) tyres offer enhanced traction and durability but come with compromises. A/Ts are more versatile for mixed-use driving, while M/Ts are focused on aggressive off-road conditions and can be noisier or less efficient on tarred roads. Consider the terrain you’ll encounter most often when selecting tread patterns.
Final Thoughts
Being able to read a tyre sidewall allows you to make informed choices that affect both the performance and safety of your 4×4. From selecting the correct load rating to understanding how size and construction influence capability, these markings provide essential information—especially when upgrading for overland or off-road use.
