now coming to that figure 4. its the width of the tyre in inches. 1 inch =25.4mm so it translates into 101mm (100 mm approx). so basically 4.00 is equivalent of 100 section tyre.
hope your doubt is cleared.

BTW michelin are soft compound tyres and weigh around 30% less than their hard indian counterpart. offer better grip and mileage. costs more and lasts less.
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