Know about your vehicle tyres

Long since i have been wondering to write about this and now iget a chance.. :-)

This is about the tyres and the numbers written on them.

When you buy a car, the spec says the tyres are 175/65 R 13 as if all know about that and claim it to be superior.. (i did not know about that for long till i first thought of changing my bike tyre to a broader one.. ) and thought will be of help to others.

When you say the tyre of the size, 175/65 R13 T, This is what it means, The first number denotes the size of the breadth : How broad your tyre is. That means, a broader tyre will have a bigger number - Here it is 175. and the 65 denotes, the wall height of the tyre which is the distance from the inner side of the tyre that fits into the rim/wheels towards the outer edge that touches the road. Tyre of 175/65 will look flatter than 175/75 or 175/85. Next letter R represents it is a "radial" tyre. the number after R represents the inner diameter of the tyre. Typically, R13 (Used in Wagon R) will be smaller than R14 (Used in i10). Then finally the alphabet "T". This is the speed rating. A T rated tyre is fit to run at speeds of under 180 kms / hr.

For bikes that ply in Indian roads there's a small difference in notation. A tyre mark will typically be 18 x 3.0 this means, [some times this is reversed and given like, 3.0 x 18] 18 is the inner diameter of the tyre and 3.0 is the width of the tyre that touches the road. So 18 x 2.75 will be thinner than 18 x 3.25

One important thing.. I forgot to tell you about rating or the durability of the tyre.. When you buy one, please look for the expiry date. YES tyres have expiry date and beyond which the rubber becomes hard and cracks. This may lead to tyre bursts enroute.