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The numbers and letters on a tyre sidewall tell you its size, how much weight it can carry, how fast it is rated for and what kind of conditions it is designed to handle. Here is what each marking means without the technical overload.
A typical 4×4 tyre size might look like this:
LT265/70R17 121/118Q
Read from left to right:
LT means Light Truck. These tyres are commonly used on pickups, working 4x4s and vehicles that carry weight or spend time on difficult ground.
Not every 4×4 needs an LT tyre, so check the vehicle specification before changing from the type already recommended by the manufacturer.
265 is the tyre’s nominal width in millimetres, measured from one sidewall to the other.
It is not the exact tread width, and two tyres marked 265 can measure slightly differently depending on the manufacturer and tread design.
70 is the sidewall height expressed as a percentage of the tyre width.
On a 265/70 tyre, the sidewall is approximately 70% of 265mm, or around 185mm tall.
A taller sidewall usually gives more cushioning and more flexibility off-road. A shorter sidewall generally feels firmer and more direct on the road.
R means the tyre uses radial construction, which is standard on almost all modern road-going 4×4 tyres.
17 means it fits a 17-inch wheel. The tyre and wheel diameter must match exactly.
The load index tells you how much weight the tyre is designed to carry.
In the example 121/118:
Load index 121 equals a maximum load of 1,450kg per tyre under the correct conditions.
Do not choose a load index simply by dividing the vehicle’s weight by four. Use the vehicle handbook, door sticker or approved tyre specification. Pickups and loaded 4x4s often carry more weight over one axle than the other.
The letter after the load index is the tyre’s speed rating.
Common 4×4 tyre ratings include:
Aggressive mud-terrain tyres often have lower speed ratings than road-focused tyres because they are designed around off-road traction rather than high-speed driving.
Use a speed rating that is suitable for the vehicle. Do not automatically fit a lower rating just because you do not plan to drive at the tyre’s maximum speed.
Some off-road tyres use imperial sizing instead of metric sizing.
For example:
35×12.50R15
This means:
A 265/70R17 tyre is approximately 31.6 inches tall, so moving to a 35-inch tyre is a meaningful increase.
Before fitting larger tyres, check wheel width, arch clearance, suspension clearance, steering lock, gearing and speedometer accuracy.
PR means ply rating. It describes the tyre’s strength category rather than the literal number of layers inside it.
You may also see an American load-range letter:
A higher rating normally means greater load and pressure capability, but it can also mean a heavier tyre and a firmer ride.
Higher does not automatically mean better. Choose a rating that suits the vehicle, the weight it carries and the way it is used.
M+S means Mud and Snow.
It is commonly found on all-terrain and mud-terrain tyres, but it does not mean the tyre has passed a formal winter performance test.
The three-peak mountain snowflake symbol shows a snowflake inside a mountain.
A tyre carrying this symbol has met a recognised snow-traction test. It is the more meaningful marking if you regularly drive in genuine winter conditions.
The manufacturing date is shown as a four-digit code on the sidewall.
For example:
1024 means the tyre was made in week 10 of 2024.
Tyres do not have a simple five-year expiry date, but age still matters. Check older tyres carefully for:
Tread depth alone does not tell you whether an older tyre is still in good condition.
If the tyre has a rotation arrow, it must point in the direction the tyre travels when the vehicle moves forwards.
If it is marked Inside and Outside, the side marked Outside must face away from the vehicle.
These markings matter. A tyre fitted the wrong way around may not clear water, mud or loose ground as its manufacturer intended.
Most modern 4×4 tyres are tubeless. Do not add an inner tube to a tubeless setup without checking that the tyre, wheel and tube are compatible.
An E-mark shows that the tyre has received the relevant type approval for its category.
Be careful with specialist tyres marked:
A tyre is not automatically suitable for road use just because it fits the wheel.
The current sidewall is a useful starting point, but a previous owner may have fitted the wrong size, load rating or tyre type.
Check the vehicle handbook, tyre placard or verified fitment information before ordering replacements.
This is particularly important on four-wheel-drive vehicles. Differences in tyre size, tread depth or overall circumference can place additional strain on some four-wheel-drive systems.
Everything else helps you understand the tyre, but those four points decide whether it is the right fit.
Send Mudslingerz your vehicle details and a clear photo of the complete sidewall markings. We’ll help you identify what is fitted and which tyre options suit the vehicle, the weight it carries and the terrain it covers.
