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Tire sidewall markings decoder

# Tire sidewall markings decoder

## What do the markings on a tire sidewall mean?

A tire sidewall carries a structured set of markings that describe the tire'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 tire), 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 tire is appropriate for your vehicle, driving conditions, and legal requirements.

## Decode a tire size

Type the main sidewall size string to see the width, profile and sidewall math.

Tire size

### 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.

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## The primary size string decoded

The main tire 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 tire 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) tires; 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 tires are R. |
| **Rim diameter** | 16 | inches | The diameter of the rim the tire is designed to mount on. Must match exactly — a 16" tire will not seal on a 17" rim. |
| **Load index** | 91 | — | A code representing the maximum load per tire 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 tire 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](https://tirefitlab.com/learn/how-to-read-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](https://tirefitlab.com/learn/load-index/).

## Speed rating quick reference

| Symbol | Max speed (km/h) | Max speed (mph) | Typical application |
| --- | --- | --- | --- |
| **N** | 140 | 87 | Temporary spare tires |
| **Q** | 160 | 99 | Winter tires (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 tires (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](https://tirefitlab.com/learn/speed-rating/).

## 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. Tires 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 tire 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 tire. Required by law as the minimum winter tire standard in Germany, Austria, and other markets from November to April. | This is the only marking that legally qualifies a tire as winter-rated in regulated markets. |
| **XL or Extra Load (EL) / Reinforced (RF)** | Sidewall | The tire is built to carry higher loads than a standard (SL) tire of the same size. The rated load capacity (at max pressure) is higher. XL tires 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 tires to the same pressure as SL — check vehicle door sticker for XL-specific pressures. |
| **Max Load ___ kg / ___ lbs** | Sidewall | The maximum load per tire 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 tire can safely hold. This is NOT the recommended operating pressure. Inflating to max pressure for normal driving over-inflates the tire, 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 tires) | Uniform Tire Quality Grading. Treadwear: a comparative wear rating vs a reference tire (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 tires of the same brand. Do not compare across brands — testing methods differ. |
| **OUTSIDE / ASYMMETRIC** | Sidewall | Indicates the tire 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 tires 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 tire 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 tire designations. The tire 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 tire guide. |
| **Made in ___** | Sidewall | Country of manufacture. Required labelling in most markets. The manufacturing location of tires from international brands varies — it does not indicate the brand origin country. | Informational only. |
| **E mark (e followed by a number)** | Sidewall (European tires) | 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 tire meets ECE Regulation R30 (passenger car) or R54 (commercial) standards. | All new tires sold legally in Europe carry this mark. |

## OEM tire markings: source-checked reference

An Original Equipment (OE) mark identifies a tire version developed and approved for a vehicle maker, often for a particular model or application. It is more specific than the tire model name alone.

| Sidewall marking | Vehicle maker | What the mark supports | What it does not prove |
| --- | --- | --- | --- |
| **★ (star)** | BMW / MINI | A BMW-tested, vehicle-tuned tire version. | Approval for every BMW model or wheel size. |
| **AO / AO1 / RO1 / RO2** | Audi | An Audi Genuine tire version tested against model-specific criteria. | Rolls-Royce approval; RO1 and RO2 are Audi markings. |
| **MO / MOE / MO1 family** | Mercedes-Benz / Mercedes-AMG | A Mercedes OE version; MOE identifies an extended-mobility variant. | Interchangeability between every MO-family version. |
| **N / N0 / N1 and newer N-series codes** | Porsche | A tire version tested and approved by Porsche for specified applications. | That every N-marked version suits every Porsche model or axle. |
| **VOL** | Volvo | A Volvo-tested and customized tire version for a specified model. | That size, load index, speed rating and axle position can be ignored. |

Match the exact vehicle, model, axle and tire specification in the owner manual or manufacturer-approved tire list. An OE mark does not replace the required size, load index, speed rating, wheel compatibility, pressure or physical-clearance checks.

## 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 tire's age is counted from this date, not from when it was purchased. Tire 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](https://tirefitlab.com/learn/tire-age/).

## Max pressure vs recommended pressure: a critical distinction

The sidewall prints the maximum structural pressure the tire 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 tire pressure guide](https://tirefitlab.com/learn/cold-tyre-pressure/).

## More tools

- [How to read a tire size](https://tirefitlab.com/learn/how-to-read-tire-size/)
- [Load index chart](https://tirefitlab.com/learn/load-index/)
- [Speed rating chart](https://tirefitlab.com/learn/speed-rating/)
- [Tire age guide](https://tirefitlab.com/learn/tire-age/)
- [Cold tire pressure guide](https://tirefitlab.com/learn/cold-tyre-pressure/)
- [Run-flat tire guide](https://tirefitlab.com/learn/run-flat-tyres/)
- [TPMS guide](https://tirefitlab.com/learn/tpms/)
- [Tire & wheel reference guides](https://tirefitlab.com/learn/)

## OEM marking sources reviewed

The mappings above are limited to markings confirmed by vehicle-maker material or a current tire-manufacturer OE reference. Manufacturer guidance remains authoritative for the exact vehicle and tire version.

- [BMW: Genuine star-marked tires and model-specific testing](https://www.bmw.com/en-au/offers-and-services/bmw-original-accessories/travel-transport-solutions.html)
- [Audi: AO, AO1, RO1 and RO2 Audi Genuine tire markings](https://media.audi.com/is/content/audi/nemo/australia/Owners/audi_genuine_parts/Brochures/tyres_mar18.pdf)
- [Porsche: N-marked tires tested and approved for Porsche applications](https://www.porsche.com/stories/innovation/summer-wheels-and-tyres/)
- [Volvo: VOL-marked Genuine Tires and model-specific development](https://www.volvocars.com/us/l/genuine-tires/)
- [Michelin: current OE-marking table by vehicle manufacturer](https://www.michelin.co.uk/auto/advice/tyre-basics/tyre-markings-explained)

Checked: 2026-08-21

[Last reviewed: 2026-08-21](https://tirefitlab.com/methodology/)

Seasonal check

## Planning a long summer drive?

Use the budget and running-cost tools before a trip, especially if the current tires are worn or the replacement size changes diameter.

[Estimate tire budget](https://tirefitlab.com/tire-budget-calculator/)

## More in this topic: Size validation

Decode markings, compare sizes, and understand diameter, load and speed changes.

- [**How to read a tire size** How to read a tire size: decode every number and letter in P205/55R16 91V — width, aspect ratio, rim diameter, load index, speed rating.](https://tirefitlab.com/learn/how-to-read-tire-size/)
- [**Tire type guide — P, LT, metric, radial & flotation** What do the letters in a tire size mean? P, LT, metric, radial (R) and flotation tire types explained.](https://tirefitlab.com/learn/tire-types/)
- [**Tire load index chart** Use the tire load index chart to convert ratings 60–130 into kg and lb, then verify the vehicle placard and axle-load requirements.](https://tirefitlab.com/learn/load-index/)
- [**Tire speed rating chart** Use the tire speed rating chart to convert symbols from L to Y/ZR into km/h and mph for replacement tire checks.](https://tirefitlab.com/learn/speed-rating/)

### Useful tools

[Tire size converter (mm ↔ inches)](https://tirefitlab.com/tire-size-converter/)[Tire size calculator](https://tirefitlab.com/tire-size-calculator/)