Tyre sidewall markings decoder
What do the markings on a tyre sidewall mean?
A tyre sidewall carries a structured set of markings that describe the tyre's size, construction, load capacity, speed capability, age, and legal certifications. The primary size string — for example 205/55 R16 91V — encodes section width (205 mm), aspect ratio (55%), construction type (R = radial), rim diameter (16 inches), load index (91 = 615 kg per tyre), and speed rating (V = up to 240 km/h). Additional markings include the DOT code (manufacturing date and plant), M+S or 3PMSF snowflake (winter ratings), UTQG treadwear / traction / temperature grades (USA), the maximum inflation pressure (not the recommended pressure), and country of manufacture. Reading all the markings on the sidewall before purchase ensures the tyre is appropriate for your vehicle, driving conditions, and legal requirements.
- A tyre sidewall carries a structured set of markings that describe the tyre's size, construction, load capacity, speed capability, age, and legal certifications.
- The primary size string — for example 205/55 R16 91V — encodes section width (205 mm), aspect ratio (55%), construction type (R = radial), rim diameter (16 inches), load index (91 = 615 kg per tyre), and speed rating (V = up to 240 km/h).
- Additional markings include the DOT code (manufacturing date and plant), M+S or 3PMSF snowflake (winter ratings), UTQG treadwear / traction / temperature grades (USA), the maximum inflation pressure (not the recommended pressure), and country of manufacture.
FAQ
- What do the markings on a tyre sidewall mean?
- A tyre sidewall carries a structured set of markings that describe the tyre's size, construction, load capacity, speed capability, age, and legal certifications. The primary size string — for example 205/55 R16 91V — encodes section width (205 mm), aspect ratio (55%), construction type (R = radial), rim diameter (16 inches), load index (91 = 615 kg per tyre), and speed rating (V = up to 240 km/h). Additional markings include the DOT code (manufacturing date and plant), M+S or 3PMSF snowflake (winter ratings), UTQG treadwear / traction / temperature grades (USA), the maximum inflation pressure (not the recommended pressure), and country of manufacture. Reading all the markings on the sidewall before purchase ensures the tyre is appropriate for your vehicle, driving conditions, and legal requirements.
- What should I verify before using this information?
- Use TireFitLab values as a sizing reference, then verify the vehicle handbook, tire placard, rim compatibility, load rating, and physical clearance before fitting.
Decode a tyre size
Type the main sidewall size string to see the width, profile and sidewall math.
- Section width
- 205 mm
- Aspect ratio
- 55%
- Sidewall height
- 112.8 mm
- Overall diameter
- 631.9 mm
Reference-table value only. Always match your vehicle placard and tire sidewall markings.
The primary size string decoded
The main tyre designation — e.g. 205/55 R16 91V — is printed in large text on both sidewalls. Each element has a specific meaning:
| Field | Example value | Unit | What it means |
|---|---|---|---|
| Section width | 205 | mm | The width of the tyre from sidewall to sidewall (not tread width) when mounted on the specified rim width at the specified inflation pressure. Sometimes called "nominal section width". |
| Aspect ratio (profile) | 55 | % of section width | The sidewall height expressed as a percentage of the section width. 205 × 55% = 112.75 mm sidewall height. Lower numbers mean lower-profile (sportier) tyres; higher numbers mean taller sidewalls (more comfort, more load deflection). |
| Construction | R | — | R = Radial (dominant since the 1980s). B = Bias-belted. D = Diagonal (cross-ply). Virtually all modern passenger car tyres are R. |
| Rim diameter | 16 | inches | The diameter of the rim the tyre is designed to mount on. Must match exactly — a 16" tyre will not seal on a 17" rim. |
| Load index | 91 | — | A code representing the maximum load per tyre at the rated inflation pressure. LI 91 = 615 kg. Must be equal to or higher than the minimum specified for your vehicle (on the door sticker). |
| Speed rating | V | — | The maximum sustained speed the tyre is designed to handle under load and at rated pressure. V = 240 km/h. Must equal or exceed the OEM minimum for your vehicle. |
For a full breakdown of the size string with a visual guide and worked examples, see our How to read a tire size.
Load index quick reference (common values)
| Load index | Max load (kg) | Max load (lbs) |
|---|---|---|
| 75 | 387 | 853 |
| 80 | 450 | 992 |
| 85 | 515 | 1135 |
| 87 | 545 | 1202 |
| 88 | 560 | 1235 |
| 89 | 580 | 1279 |
| 90 | 600 | 1323 |
| 91 | 615 | 1356 |
| 92 | 630 | 1389 |
| 94 | 670 | 1477 |
| 96 | 710 | 1565 |
| 98 | 750 | 1653 |
| 100 | 800 | 1764 |
| 102 | 850 | 1874 |
| 105 | 925 | 2040 |
For the full 71–121 load index table with all kg/lb values, see our Load index chart.
Speed rating quick reference
| Symbol | Max speed (km/h) | Max speed (mph) | Typical application |
|---|---|---|---|
| N | 140 | 87 | Temporary spare tyres |
| Q | 160 | 99 | Winter tyres (studded or heavy winter) |
| R | 170 | 106 | Heavy-duty light truck |
| S | 180 | 112 | Family saloons, vans |
| T | 190 | 118 | Saloons, SUVs, vans |
| H | 210 | 130 | Sports cars, performance saloons |
| V | 240 | 149 | Sports cars, performance vehicles |
| W | 270 | 168 | High-performance sports cars |
| Y | 300 | 186 | Ultra-high-performance and supercars |
| ZR | 240+ | 149+ | High-performance tyres (legacy designation, used with W/Y) |
For the full speed symbol table and what happens when you exceed the rated speed, see our Speed rating chart.
Additional sidewall markings
| Marking | Location | What it means | Action |
|---|---|---|---|
| DOT XXXX XXXX 4 digits | Outboard sidewall | The last four digits are the manufacturing date: first two = week (01–52), last two = year. e.g. DOT ... 2422 = week 24 of 2022. Tyres over 6–10 years old from the DOT date (not purchase date) should be inspected or replaced regardless of tread depth. | Check for age compliance. See our tire-age guide for replacement thresholds. |
| M+S or M&S | Sidewall | Mud and Snow rating. A self-certification by the manufacturer indicating traction in mud/snow conditions. Does NOT require testing to an objective standard. M+S alone does not qualify as a winter tyre under EU/German regulations — it is a marketing designation. | Do not rely on M+S alone for legal winter compliance in regulated markets. |
| 3PMSF (Three-Peak Mountain Snowflake) | Sidewall — a mountain outline with a snowflake inside | An objectively tested and certified winter performance rating. Must pass the Snow Traction Index (STI) test with ≥110% score vs a reference tyre. Required by law as the minimum winter tyre standard in Germany, Austria, and other markets from November to April. | This is the only marking that legally qualifies a tyre as winter-rated in regulated markets. |
| XL or Extra Load (EL) / Reinforced (RF) | Sidewall | The tyre is built to carry higher loads than a standard (SL) tyre of the same size. The rated load capacity (at max pressure) is higher. XL tyres require a minimum inflation pressure of 2.9 bar (42 PSI) to achieve their rated load capacity. Often needed on heavier vehicles using the same size rim as lighter ones. | Do not inflate XL tyres to the same pressure as SL — check vehicle door sticker for XL-specific pressures. |
| Max Load ___ kg / ___ lbs | Sidewall | The maximum load per tyre at the maximum inflation pressure stated next to it. This is the structural design limit, not the recommended operating load. Operating at or near max load requires the max pressure shown. | For normal driving, use the vehicle door-sticker pressure — not the sidewall max pressure. |
| Max Pressure ___ kPa / ___ PSI / ___ bar | Sidewall, near max load marking | The maximum structural inflation pressure the tyre can safely hold. This is NOT the recommended operating pressure. Inflating to max pressure for normal driving over-inflates the tyre, causing centre-tread wear, reduced grip, and harsh ride. | Ignore this for normal use. Always set pressure to the vehicle door-sticker specification (cold). |
| UTQG: Treadwear ___ Traction _ Temperature _ | Sidewall (USA-market tyres) | Uniform Tire Quality Grading. Treadwear: a comparative wear rating vs a reference tyre (100 = reference). 400 wears 4× longer than 100. Traction: A/A = best, C = poor (wet braking on asphalt and concrete). Temperature: A/B/C = heat resistance at sustained speed. Required by US NHTSA. | Useful for comparing wear life and wet traction between tyres of the same brand. Do not compare across brands — testing methods differ. |
| OUTSIDE / ASYMMETRIC | Sidewall | Indicates the tyre has an asymmetric tread pattern with a specific outboard (road-facing) and inboard side. The word OUTSIDE must face away from the vehicle. Mounting asymmetric tyres inside-out is a serious safety error that negates the tread design. | Confirm OUTSIDE faces outward on all four corners after fitting. |
| Direction arrow | Sidewall | Indicates a directional (unidirectional) tread pattern. The tyre must rotate in the direction shown. Fitted in the wrong direction, the V-shaped tread channels cannot expel water efficiently and aquaplaning resistance is severely degraded. | Check rotation direction matches the arrow when fitting and after any wheel removal. |
| Run Flat / SST / RFT / ROF / EMT / SSR / DSST | Sidewall | Brand-specific run-flat tyre designations. The tyre has a reinforced sidewall that supports the vehicle at zero pressure for up to 80 km at 80 km/h. Requires a TPMS system to warn the driver of pressure loss (run-flats have no perceptible handling change when flat). | Run-flats cannot be repaired after zero-pressure running. See our run-flat tyre guide. |
| Made in ___ | Sidewall | Country of manufacture. Required labelling in most markets. The manufacturing location of tyres from international brands varies — it does not indicate the brand origin country. | Informational only. |
| E mark (e followed by a number) | Sidewall (European tyres) | European type-approval mark. The number indicates the approving country (e.g. e11 = UK, e4 = Netherlands). Required for sale in EU and EEA markets. Indicates the tyre meets ECE Regulation R30 (passenger car) or R54 (commercial) standards. | All new tyres sold legally in Europe carry this mark. |
OEM fitment markings (vehicle-specific approvals)
Some tyres carry vehicle manufacturer approval markings on the sidewall. These are printed as small letters or codes and indicate the tyre has been specifically tuned and tested for a particular model:
- * (star) — BMW/Mini: the tyre has a BMW-specific compound, noise foam, or rolling resistance target. BMW vehicles may recommend or require * tyres for optimal ride quality and range.
- MO — Mercedes-Benz Original: tyre meets Mercedes fitment criteria. Includes noise characteristics and compound calibration for Mercedes suspension.
- AO — Audi Original / VOL — Volvo / RO1 — Rolls-Royce: similar OEM designations from other manufacturers. The tyre specification (compound stiffness, noise, rolling resistance) was co-developed or approved by the vehicle manufacturer.
- SSR / RSC / RFT / ROF / EMT: run-flat designations. See our Run-flat tyre guide.
OEM-approved tyres are not legally required as replacements — you can fit any tyre of the correct size and load/speed rating. However, OEM-spec tyres are tuned for the vehicle's suspension, so substituting standard tyres may change ride quality, noise levels, or range (for EVs).
DOT code: reading the manufacturing date
The DOT code appears on one or both sidewalls. The last four digits give the manufacture date:
- First two digits = week of manufacture (01–52)
- Last two digits = year of manufacture
- Example: DOT ... 2422 = week 24 of 2022 = manufactured in June 2022
A tyre's age is counted from this date, not from when it was purchased. Tyre rubber degrades over time due to ozone, UV, and oxygen — regardless of use. Most manufacturers recommend replacement after 6 years from the DOT date; the maximum safe service life is 10 years. For full age thresholds and how to find the DOT code, see our Tire age guide.
Max pressure vs recommended pressure: a critical distinction
The sidewall prints the maximum structural pressure the tyre can hold. This is typically 3.5–4.5 bar (51–65 PSI). It is not the pressure you should use for normal driving.
The correct operating pressure is on the vehicle door jamb sticker and in the owner manual. This is a cold-tyre specification (after 3+ hours at rest or less than 1.6 km driven). The typical range for passenger cars is 2.0–2.8 bar (29–41 PSI).
Inflating to the sidewall max pressure while driving on a normal road will cause: centre-tread wear, reduced wet grip (smaller contact patch), harsh ride, and increased susceptibility to impact damage. For more on the cold pressure rule and seasonal adjustment, see our Cold tyre pressure guide.
More tools
- How to read a tire size
- Load index chart
- Speed rating chart
- Tire age guide
- Cold tyre pressure guide
- Run-flat tyre guide
- TPMS guide
- Tire & wheel reference guides
Seasonal check
Planning a long summer drive?
Use the budget and running-cost tools before a trip, especially if the current tyres are worn or the replacement size changes diameter.
What changed
- Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.