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Your Tyre Size
Tyre Size CalculatorCalculated valuesUnit
Tyre Diameter0mm
Static Radius0mm
Dynamic Radius0mm
Rev / Kms0Rev / Kms

For example tyre size 165/75R14 has:
Tyre Width = 165 mm. This is the linear distance between the outside sidewalls of an inflated tyre without any load.

Aspect Ratio is the sidewall height as a percentage of the section width. For example, sidewall height of this tyre will be 165 x 0.75 = 123.75 mm
Tyre type = R - Radial-ply structure
Rim Diameter = 14 inches

Tyre DiameterThis is the Geometrical diameter of an inflated tyre at the outermost surface of the tread, or twice the inflated section height of tyre plus nominal wheel rim radius. Tyre diameter is dependent on Tyre width, aspect ratio and wheel rim diameter. In service condition tyre diameter increases marginally due to carcass relaxation. The tyre diameter acts just like another gear in your vehicle and matters a lot in defining the economy and vehicle acceleration.
Static RadiusStatic rolling radius or "Static radius" is the distance between wheel center and the point on the circumference of a tyre taking compression into account. It defines vehicle stance and ground clearance in static condition. Due to tyre compression at corresponding load ,tyre static radius reduces from normal geometrical radius.
Dynamic RadiusDynamic rolling radius is the actual radius of tyre when the vehicle is moving. This takes into account the centrifugal force that acts upon the tyre during revolutions.
CircumferenceThe linear distance traveled by a tyre in one revolution. It is derived from from Dynamic rolling radius as it represents the true radius of tyre during motion. It is useful to compute tyre speedometer and odo meter calibration errors.
Rev / KmsMeasured number of revolutions for a tyre traveling one kilometer. This can vary with load and inflation pressures.