How To Read Your Tyre Size

It’s easier than you think to understand tyre size!

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Read your tyre size

Why should I know my tyre size?

Knowing your car's tyre size will help you choose tyres that last longer, perform better and save you money!

Whatever model of car, 4x4, SUV, or light van you drive, booking a tyre replacement at your nearest Tony's store means fitting high quality tyres that improve the safety, durability and fuel efficiency of your vehicle.

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How do I find my tyre size?

It’s easy to find your tyre size, simply look for the manufacturer’s name on the sidewall of your tyre and next to that you’ll see a series of numbers and letters. Each has a specific meaning related to tyre size, tyre profile and how the tyre was made.

Tyre size by the numbers

Using the example above: 205/40R17

205 is the width of your tyre in millimetres.
40 is the aspect ratio or tyre profile.
R means it is radial construction.
17 is the diameter of your wheel rim in inches.

Tyre size terms explained

It's not always obvious what things mean when it comes to tyre size. To help, here are some easy explanations of some key tyre size terms.

Tyre Width

Tyre width is simply the width of your tyre in millimetres as measured from the inner sidewall to the outer sidewall and is the first number shown in the combination of numbers and letters above.

Aspect Ratio/Tyre Profile

Your aspect ratio, more clearly referred to as your tyre profile, is a measurement of the height of your tyre sidewall expressed as a percentage of the tyre width. So if your aspect ratio is 65, it means your tyre sidewall height is 65 percent of your tyre width.

Tyre Construction

Tyre construction describes the method used to construct your tyres. 'R' for radial ply construction is the most common for passenger tyres. Remember to always check with a Tony's tyre specialist before changing an original equipment (OE) rim or manufacturer-fitted tyre.

Rim Size

Rim size indicates the diameter of your wheel rim and is the distance measured in inches between the two opposite wheel flanges.

Load Index

Load index or load rating is a two-digit number that refers to the maximum weight capacity your tyre can carry at full speed.

Speed Index

Your speed index is a letter from E to Z which denotes the recommended maximum speed you can travel before your tyre will start to fail.

Tyre size information

You can find tyre size and tyre related information in your car's owner's manual or via a placard fitted to your vehicle. It might include recommended tyre pressures alongside a reminder to consult a tyre professional before fitting aftermarket wheels and tyres.

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What are Load and Speed Index?

Both the load and speed index are indicators of how much weight your tyres can safely carry and at what speed, represented by a two-digit number and a letter. In the example above, load and speed index is 91V, indicating a maximum load of 615 kg at 240km/h max speed.

Tyre speed rating chart

This is the maximum speed at which your tyre can be safely operated when your tyres are in good condition, correctly fitted and inflated to the recommended tyre pressure.

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 index table

This table indicates the maximum load capacity at which a tyre can be safely operated when the tyre is in good condition, is correctly fitted and inflated to the recommended tyre pressure.

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