Understanding Tyre Sizes

Calculate Tyre Size

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How to check your tyre size
Width

Profile

Rim

Load

Speed

Indicates the section width of a tyre in millimetres.

The sidewall height measured from the base of the tread to the rim. This number represents a percentage of the tread width. Low profile tyres have smaller aspect ratio percentages.

Indicates the diameter of the wheel rim. So if you are buying wheels for existing tyres, this is the size in inches you will require.

Load indicates the maximum load capacity at which a tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted and with the recommended inflation pressure. See table below for load index and the maximum load per tyre.

Load index 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

Max load/tyre (kg) 487 500 515 530 545 560 580 600 615 630 650 670 690 710 730 750 775

Speed symbol is a code which indicates the speed at which a tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted and with the recommended inflation pressure. See table below for passenger tyre speed symbol ratings.

Symbol E F G J K L M N P Q R S T U H V W Y Z

Rating 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 240 270 300 240+

Tyre size explained

Tyre dimensions

Width:
The section width of your tyre in millimetres, from the inner sidewall to the outer sidewall. Example: 195mm

Aspect Ratio:
The height of your tyre from the base of the tread to the rim, as a percentage of the tread width. Low profile tyres have smaller aspect ratios. Example: The height of this tyre is 65% of its width.

Tyre Construction:
The method used to construct your tyre. Example: R, for radial ply construction. This is the most common method of construction for passenger tyres.

Rim:
The diameter of the wheel rim in inches. If you are buying wheels for existing tyres, this is the size you will need. Example: 15 inches.

Load Index and Speed Symbol
The maximum load capacity under which your tyre can safely operate, and at what speed. This is subject to the tyre being in sound condition, correctly fitted, and with the recommended inflation pressure. Example: 91 V

Tyre speed rating chart

Tyre speed symbol table

Speed symbol is a code which indicates the speed at which a tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted and with the recommended inflation pressure. See table below for passenger tyre speed symbol ratings.

Speed Symbol	Rating (Km/h)
E	70
F	80
G	90
J	100
K	110
L	120
M	130
N	140
P	150
Q	160
R	170
S	180
T	190
U	200
H	210
V	240
W	270
Y	300
Z	240+

Tyre load rating chart

Tyre load index table

Load indicates the maximum load capacity at which a tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted and with the recommended inflation pressure. See table below for load index and the maximum load per tyre.

Load Index	Max Load (kg)	Load Index	Max Load (kg)	Load Index	Max Load (kg)	Load Index	Max Load (kg)	Load Index	Max Load (kg)	Load Index	Max Load (kg)
60	250	85	515	110	1060	135	2180	160	4500	185	9250
61	257	86	530	111	1090	136	2240	161	4625	186	9500
62	265	87	545	112	1120	137	2300	162	4750	187	9750
63	272	88	560	113	1150	138	2360	163	4875	188	10000
64	280	89	580	114	1180	139	2430	164	5000	189	10300
65	290	90	600	115	1215	140	2500	165	5150	190	10600
66	300	91	615	116	1250	141	2575	166	5300	191	10900
67	307	92	630	117	1285	142	2650	167	5450	192	11200
68	315	93	650	118	1320	143	2725	168	5600	193	11500
69	325	94	670	119	1360	144	2800	169	5800	194	11800
70	335	95	690	120	1400	145	2900	170	6000	195	12150
71	345	96	710	121	1450	146	3000	171	6150	196	12500
72	355	97	730	122	1500	147	3075	172	6300	197	12850
73	365	98	750	123	1550	148	3150	173	6500	198	13200
74	375	99	775	124	1600	149	3250	174	6700	199	13600
75	387	100	800	125	1650	150	3350	175	6900	200	14000
76	400	101	825	126	1700	151	3450	176	7100	201	14500
77	412	102	850	127	1750	152	3550	177	7300	202	15000
79	437	104	900	129	1850	154	3750	179	7750	204	16000
80	450	105	925	130	1900	155	3875	180	8000	205	16500
81	462	106	950	131	1950	156	4000	181	8250	206	17000
82	475	107	975	132	2000	157	4125	182	8500	207	17500
83	487	108	1000	133	2060	158	4250	183	8750	208	18000
84	500	109	1030	134	2120	159	4375	184	9000	209	18500

OD:
The overall diameter of your unloaded tyre in mm.

Type Definitions:
An abbreviation providing information about the type of your tyre.

Examples:
RFT – Run Flat Technology
MOE – Mercedes Original Equipment
LRR – Low Rolling Resistance
RBT – Raised Black Letters Tubeless
OWT – Outline White Letters Tubeless
RWT – Raised White Letters Tubeless
LWT – Line White Tubeless
TT – Tube Type
TL – Tubeless
XL – Extra Load
LT – Light Truck construction
N* - Porsche specification
☆ – BMW spec

Our Run-Flat Technology

If your tyre is punctured while driving, you’ll experience loss of tyre pressure that can cause you to lose steering control, endangering yourself and the cars around you. You’ll also face further risk while changing the tyre on the roadside or waiting for mechanics to arrive.

When a Run Flat tyre is punctured, there is no sudden deflation. Instead, you can continue to drive safely, despite a total loss of air pressure. Run Flat tyres are built with thicker, reinforced sidewalls, along with heat resistant rubber, to keep the tyre from collapsing so you can continue to a safe location. Tyres with Run Flat Technology should only be fitted to vehicles that are equipped with a Tyre Pressure Monitoring System (TPMS).

Please check with your vehicle manufacturer to see if your vehicle can be fitted with Run Flat tyres.

Learn more about Bridgestone's run flat technology.

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Frequently asked questions

What tyre size should I choose for my car?

We recommend you choose the tyre size identified by your car’s manufacturer on your vehicle tyre placard. Changing your tyre size from the manufacturer’s standard may mean your car is no longer roadworthy, and might not be covered by your insurance. Use our tyre size calculator to find the right tyre size for your vehicle.
How do you determine which tyres fit my vehicle?

We use your vehicle’s original tyre size to determine which tyres fit your vehicle. If you use our online tyre size calculator, it’s important that you enter your vehicle’s make, model, and year correctly. You may also search for tyres using your vehicle’s registration or tyre size.
What do the numbers on the sidewall of my tyre mean?
The sidewall of your tyre is the part between the edge of the wheel and the tread. If you look closely at the sidewall, you will notice a series of numbers that give you important information about your tyre’s specifications.
Width

Aspect

Rim Size

Load

Speed

The section width of your tyre in millimetres.

The sidewall height measured from the base of the tread to the rim. This number represents a percentage of the tread width. Low profile tyres have smaller aspect ratio percentages.

The diameter of the wheel rim in inches. This is the size you will need to choose if you are buying wheels for an existing tyre.

The maximum load capacity at which your tyre can be safely operated. This is subject to your tyre being in sound condition, correctly fitted and inflated at the recommended pressure.

A code indicating the speed at which your tyre can be safely operated. Again, this is subject to your tyre being in sound condition, correctly fitted and inflated at the recommended pressure.