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Tyre size calculator, showing how to calculate your tyre size. Image of tyre width size.

Tyre size calculator, showing how to calculate your tyre size. Image of tyre rim size.

Tyre size calculator, showing how to calculate your tyre size. Image of tyre speed symbol.

Tyre size calculator, showing how to calculate your tyre size. Image of tyre load speed.

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+