Tyre Rolling Circumference
Distance covered in one wheel revolution.
Formula
Variables
Example
d=0.65 m: C ≈ 2.04 m per revolution
How it works
This formula finds the distance around a tyre by using its diameter, which is the straight-line width across the wheel through the centre. A full turn of the wheel moves the vehicle forward by one tyre circumference, because the tyre rolls without slipping and the point of contact with the road shifts by exactly one full rotation around the edge. The factor of π appears because the circumference of any circle is π times its diameter.
When to use it
Use this when you want to estimate how far a vehicle travels per wheel revolution, such as in speed calculations, odometer calibration, gearing problems, or comparing tyre sizes. It is especially useful in automotive maths where wheel rotation needs to be converted into road distance.
Worked example, step by step
Given tyre diameter d = 0.72 m Use the formula C = πd C = π × 0.72 C ≈ 3.1416 × 0.72 C ≈ 2.26 m So the tyre travels about 2.26 metres in one full revolution.
Common mistakes to avoid
- Using the tyre radius instead of the diameter in the formula
- Forgetting that the result is a distance per full rotation, not a speed
- Mixing units, such as putting diameter in mm and expecting the circumference in m without converting first
Did You Know?
Fitting larger tyres than standard makes the speedometer read low, since each revolution now covers more ground.
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