How to Read Tyre Size Markings: 205/55R16 Explained

# How to Read Tyre Size Markings: 205/55R16 Explained

Every tyre has a code printed on its sidewall — a sequence of numbers, letters, and symbols that defines its exact specification. Understanding these markings is essential when you need to replace a tyre, buy spares, or simply check whether the tyre on your vehicle is correct.

The Main Size Code: 205/55R16

Using the example 205/55R16:

205 — Tyre Width (in millimetres)

This is the width of the tyre across its widest point, measured in millimetres. A wider tyre provides more road contact and can improve grip, but it also increases rolling resistance and fuel consumption. Common widths range from 135mm (small city cars) to 315mm (performance SUVs).

55 — Aspect Ratio (Profile)

This is the height of the tyre sidewall expressed as a percentage of the width. So for a 205/55 tyre, the sidewall height is 55% of 205mm = 112.75mm.

• A lower profile (e.g., 35 or 40) looks sportier and improves handling precision but gives a harsher ride and is more vulnerable to pothole damage — a significant consideration on Scottish Highland roads.
• A higher profile (e.g., 65 or 70) gives a more comfortable ride and better cushioning on rough surfaces.

R — Radial Construction

The 'R' indicates radial tyre construction — the standard for all modern passenger car tyres. (The alternative, 'D' for diagonal/bias-ply, is now rare and used mainly on older vehicles and some motorcycles.)

16 — Rim Diameter (in inches)

This is the diameter of the wheel rim the tyre fits onto, measured in inches. This must match your wheel exactly — a 16-inch tyre will only fit a 16-inch rim.

Additional Markings: Speed Rating and Load Index

After the main size code, you will typically see two more characters, e.g., 91V or 88H.

Load Index (the number)

The load index tells you the maximum weight each tyre can carry. Common values:

Load Index	Max Load per Tyre
80	450 kg
88	560 kg
91	615 kg
95	690 kg
101	825 kg

Never fit a tyre with a lower load index than specified for your vehicle. The recommended load index is in your vehicle handbook and on the tyre placard (inside the driver's door or fuel cap).

Speed Rating (the letter)

The speed rating indicates the maximum sustained speed the tyre is designed for. Common ratings:

Letter	Max Speed
S	180 km/h (112 mph)
T	190 km/h (118 mph)
H	210 km/h (130 mph)
V	240 km/h (149 mph)
W	270 km/h (168 mph)
Y	300 km/h (186 mph)

In Scotland, national speed limit roads top out at 70mph (113 km/h), so any common speed rating is technically sufficient for legal road use. However, always match or exceed the speed rating specified for your vehicle.

Other Tyre Sidewall Markings

M+S or M&S

Mud and Snow. A tyre with this marking is designed for light winter conditions. Note: M+S alone does NOT mean it meets the Three Peak Mountain Snowflake (3PMSF) standard for severe winter performance.

Three Peak Mountain Snowflake (3PMSF)

A mountain symbol with a snowflake inside indicates the tyre has passed tests for severe snow performance. This is the true winter tyre certification. For Scottish Highland drivers, look for this symbol.

Run Flat Markings

Different manufacturers use different codes:

• BMW / MINI: RSC (Run-flat System Component)
• Bridgestone: RFT or RUN FLAT
• Continental: SSR (Self Supporting Runflat)
• Dunlop: DSST (Dunlop Self-Supporting Technology)
• Goodyear: ROF (Run On Flat)
• Michelin: ZP (Zero Pressure)
• Pirelli: RF or RUN FLAT

XL or Extra Load

Indicates a reinforced tyre that can carry more weight than a standard tyre of the same size. Often found on SUVs and larger estate cars. If your vehicle spec requires XL tyres, only fit XL-rated replacements.

EU Tyre Label Ratings

Look for a QR code or text indicating:

• Fuel efficiency (A–G): A is most efficient
• Wet grip (A–G): A is best braking performance in wet conditions
• Noise (dB): lower is quieter

Where to Find Your Tyre Size

If you are unsure what size you need:

1. On the tyre itself: Look at the sidewall of any of your existing tyres
2. Driver's door placard: Sticker inside the driver's door frame
3. Fuel cap sticker: On some vehicles
4. Vehicle handbook: In the specification section
5. Online lookup: Your vehicle registration number can be used to check recommended tyre sizes

Ordering Tyres Through Tyre Rescue

When you call 0141 266 0690 or [book online](/book), have your tyre size ready. We will confirm availability, quote a price for your chosen brand tier (budget, mid-range, or premium), and dispatch a fitter to your location across Scotland.

[Mobile tyre fitting Scotland](/mobile-tyre-fitting) | [Best tyres for Scottish roads](/blog/best-tyres-scottish-roads-guide) | [Tyre tread depth guide](/blog/tyre-tread-depth-guide-scotland)