Tyres Sidewall Numbers, Letters, & Icons, Explained.
To some its all common sense, to others completely misunderstood, and others, a utter mystery.
You'll find every tyre sold in the UK comes with a comprehensive set of sidewall markings denoting the many details about its form and function. But do you know how to read it all correctly and understand the importance of each part? Don't be afraid to say you don't know it all, not many people do, and some think they do but don't really. Here's our guide to what you need to know.
In order of the image above, moving left to right.
- LT – “Light Truck” rating; stronger construction for vans, pickups, and heavy loads.
- Width – The tyre’s width in millimetres (mm) (sidewall to sidewall).
- Profile / Sidewall Height – The height of the sidewall as a % of the width (e.g. 70 = 70% of width).
- R – Radial construction (almost all modern tyres).
- Rim Diameter – The wheel size (in inches) the tyre fits.
- Load Rating – The maximum weight a single tyre can carry at correct pressure.
- Twin/Dual Wheel Load Rating – Max load per tyre when used in paired (dual rear wheel) setups.
- Speed Rating – The maximum speed the tyre is safely rated for (e.g. T, H, etc.).
Full Speed and Load rating chart can be found here.
- Three Peak Mountain Snowflake (3PMSF) – Certified for severe snow conditions; proper winter performance. You can read more about 3PMSF here.
- M+S – “Mud and Snow”; basic all-terrain capability (not severe winter rated).
- POR – “Professional Off-Road”; designed mainly for off-road use, not optimised for road comfort or wear.
Other markings
Other markings you can expect to find will include details relating to the tyre's manufacture, safety standards, country of origin and air pressures, most of which are self explanatory.
The E4 marking on a tyre means it is officially approved for safe road use in the EU and the UK.
- E: Confirms the tyre meets European (UN/ECE) safety regulations
- 4: Shows the approval was issued in the Netherlands
In short, it’s a certification mark proving the tyre is legal and roadworthy.
DOT Code
The main marking to look out for if you're particularly keen to understand your tyres, is the DOT code (Department of Transport code). This is visible most commonly on just one side of the tyre and it can tell you:
- Factory where it was made
- Tyre size/type code (internal)
- Manufacturer-specific code
- Date of manufacture (most important part)
Example DOT code:
DOT | 1A2B | 3C4D | 3523
Breakdown:
- DOT – Certified to U.S. safety standards
- 1A – Manufacturing plant code
- 2B – Tyre size code
- 3C4D – Manufacturer’s internal code
- 3523 – Date code