These are summer tyre from Michelin with a diameter of 21". The maximum allowed speed is R (170 km/h), and describes the maximum permissible speed of the tire.
From Protyre
90/100-21 57R Michelin Enduro Medium 90/100-21 57R | Protyre - Car Tyres
Tirendo
Michelin Enduro ( 90/100-21 TT 57R M/C, Compound HARD, Front wheel )
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