Tyre Sizes Sitemap | Blackcircles.com

How to read your tyre size

Using the example 205 / 55 R16 91V each figure breaks down as follows:

205WidthSection width in millimetres, measured across the tread.

55ProfileSidewall height as a percentage of the width — here, 55% of 205mm.

RConstructionR means radial, the standard construction for car tyres.

16DiameterThe wheel rim diameter, in inches, that the tyre fits.

91Load indexA code for the maximum weight each tyre can carry (91 = 615kg).

VSpeed ratingThe maximum speed the tyre is rated for (V = 149mph).

Where to find your tyre size

Your tyre size is printed in several places — you only need to find one:

On the sidewall of your current tyres.

In your vehicle handbook.

On the sticker inside the driver’s door sill or door jamb.

Sometimes inside the fuel filler flap.

Some vehicles list more than one approved size. Any of the manufacturer-approved sizes is fine, provided the tyres on the same axle match.

Tyre load index

On the sidewall, the load index sits between the rim diameter and the speed rating. It’s a code for the maximum weight a single tyre can safely carry at its correct pressure — not the weight of the tyre itself. In our example, 91 means each tyre can carry up to 615kg. Always fit tyres with a load index that meets or exceeds the figure specified for your vehicle.

Common car load index values
Load index	Max load (kg)	Load index	Max load (kg)
75	387	93	650
77	412	94	670
79	437	95	690
81	462	96	710
82	475	97	730
84	500	98	750
85	515	99	775
87	545	100	800
88	560	101	825
89	580	103	875
91	615	105	925
92	630	108	1000

Common car load index values

Load index

Max load (kg)

Load index

Max load (kg)

387

650

412

670

437

690

462

710

475

730

500

750

515

775

545

100

800

560

101

825

580

103

875

615

105

925

630

108

1000

Lighter and heavier indices exist either side of this range — vans, 4x4s and reinforced (XL) tyres typically carry higher load indices.

Tyre speed rating

The final letter in the tyre code is the speed rating — the maximum speed the tyre can safely sustain at its rated load. Fitting a tyre with a lower speed rating than your vehicle requires can affect safety and may invalidate your insurance, so always match or exceed the rating in your handbook.

Speed rating symbols
Symbol	Max speed (mph)	Max speed (km/h)
N	87	140
Q	99	160
R	106	170
S	112	180
T	118	190
U	124	200
H	130	210
V	149	240
W	168	270
Y	186	300

Speed rating symbols

Symbol

Max speed (mph)

Max speed (km/h)

140

160

106

170

112

180

118

190

124

200

130

210

149

240

168

270

186

300

Note the sequence isn’t strictly alphabetical — H sits between U and V. Performance tyres usually carry W, Y or ZR ratings.

Understanding the tyre label

Every new tyre sold in the UK carries a standardised performance label so you can compare models at a glance. Since the label was revised in May 2021, it grades three areas:

Fuel efficiency — rated A to E, where A is the most efficient. A set of A-rated tyres can use noticeably less fuel over their life than a lower-graded set, because lower rolling resistance means less energy is needed to keep them moving.

Wet grip — also rated A to E, measuring wet braking distance. Each grade can add roughly one to two car lengths to your stopping distance, so it’s the safety figure worth prioritising.

External noise — shown in decibels (dB) alongside a letter grade from A to C, where A is the quietest.

The current label can also display a 3PMSF (three-peak mountain snowflake) pictogram for tyres certified for severe snow, and an ice-grip pictogram for tyres that meet the ice braking standard.

Tyre Sizes: Frequently Asked Questions

How do I read the numbers on my tyre?

Read a size such as 205/55 R16 91V left to right: 205 is the width in millimetres, 55 is the profile (sidewall height as a percentage of the width), R is radial construction, 16 is the wheel diameter in inches, 91 is the load index and V is the speed rating. Match all of these when you buy.

Where do I find my tyre size?

Your size is printed on the sidewall of your current tyres, and also appears in your vehicle handbook, on a sticker in the driver’s door sill or door jamb, and sometimes inside the fuel filler flap. You only need to read it from one of these places — they all show the same code.

Can I fit a different tyre size to the one on my car?

Stick to a size approved by your vehicle manufacturer. Some cars list more than one approved fitment, and any of those is fine. Fitting a non-approved size can affect your speedometer, handling and safety systems, and may invalidate your insurance, so check your handbook or door-sill sticker before changing size.

Do all four tyres have to be the same size?

The two tyres on the same axle must always match in size, load index and speed rating. Front and rear sizes can differ on some performance and staggered-fitment vehicles, but only where the manufacturer specifies it. We recommend replacing tyres in pairs across an axle for balanced grip and even wear.

What do the load index and speed rating mean?

The load index is a code for the maximum weight one tyre can carry — for example, 91 equals 615kg. The speed rating is the final letter and shows the top speed the tyre is rated for — V is 149mph, for instance. Always fit tyres that meet or exceed the load index and speed rating your vehicle requires.

What is the legal minimum tyre tread depth in the UK?

The legal minimum tread depth in the UK is 1.6mm across the central three-quarters of the tyre, around its entire circumference. Driving on tyres below this limit risks a fine and penalty points per tyre. Many manufacturers recommend replacing tyres at 3mm for better wet braking and safety.

Symbol	Max speed (mph)	Max speed (km/h)
N	87	140
Q	99	160
R	106	170
S	112	180
T	118	190
U	124	200
H	130	210
V	149	240
W	168	270
Y	186	300

Symbol	Max speed (mph)	Max speed (km/h)
N	87	140
Q	99	160
R	106	170
S	112	180
T	118	190
U	124	200
H	130	210
V	149	240
W	168	270
Y	186	300