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?


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.

  • How can height of the tyre be less than the width? – Ashwin Jul 7 '13 at 17:39
  • 1
    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

I presume you live in india , Both of your tire choices are good but they have their own advantages and disadvantages.

Michellin Sirac(I personally owned this one):

  • Advantages: An extremely good tyre for performance as they have softer compounds , they have high stability and you can acheive a better top speed like +3 or +4 to your current top speed and a better acceleration, exceptional cornering speeds.

  • Disadvantages: Poor tyre life , If you live in a place where the roads are not that good then be ready to face at least one puncture per 3 weeks. They threads though hold good but it gets puntchered way more frequently than say an MRF.Life(~10k kms on bad roads)


  • Advantages: A very good choice if you prefer traction over performances, very good to handle indian monsoon have good wet traction but still prone to punctures(albeit not as much as the Michellins), These somehow reduce tank slappers probably because of better tracion on hot indian roads.Life(~25k kms)

  • Disadvantages: Horrible for performance, you will get better traction but way less performance.

I Would also suggest go for MRFs they last long and provide all around better tracktion but purely upto the rider's choice at the end of the day.

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