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I have a pulsar 150 bike modified with 180cc engine. I am looking for tyres(both from and rear). The tyre should have have good cornering capability and a very good grip. Till now I have. I looked at Ceat Vertigo tubeless 100/90 R and michelin sirac. I want to know what do the numbers mean (100/90 R) and how should I go about choosing a tyre based on those numbers?

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1 Answer 1

100 is the width of the tyre in millimetres. 90 is the tyre sidewall height aspect ratio. This means that the height of the tyre is 90% of its width, i.e. 100 mm × 0.9 = 90 mm. So the tyre’s sidewall is 90 mm high. This refers to a 90 mm distance between road and wheel (if we exclude compression of the tyre by the weight of the bike and rider).

And R means it is of radial construction.

Importantly, these numbers don’t really tell you about whether these tyres are suitable for the type of riding you do.

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How can height of the tyre be less than the width? –  Ashwin Jul 7 '13 at 17:39
Very easily. Most are wider than they are high. –  Rory Alsop Jul 7 '13 at 19:38
You realise the numbers refer to the tyre and not the wheel, right? –  Rory Alsop Jul 7 '13 at 19:39
no..didn't know that. –  Ashwin Jul 8 '13 at 11:01
No worries - have updated the answer to make it clearer –  Rory Alsop Jul 8 '13 at 11:07

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