Mean Piston Speed Calculator

Mean piston speed in m/s and ft/min from stroke and RPM.

How it works

1

Enter stroke & RPM

Stroke in mm and the RPM you want to check (often the rev limit).

2

Get the speed

Mean piston speed = 2 x stroke x RPM, shown in m/s and ft/min.

3

Judge the limit

Road engines usually sit below ~20 m/s; race engines push 25 m/s and beyond with the right parts.

Frequently asked questions

What is mean piston speed?

The average speed of the piston over a stroke: 2 x stroke (m) x RPM / 60. It is a better reliability guide than RPM alone because a long-stroke engine stresses parts more at the same RPM.

What is a safe piston speed?

Stock road engines typically stay under about 20 m/s. Well-built performance engines run 22-25 m/s, and full race engines go higher with forged parts. Past ~25 m/s reliability drops fast.

Why does it matter when raising the rev limit?

Lifting the limiter raises piston speed and the inertial loads on rods and pistons. Checking mean piston speed tells you whether a higher limit is sensible for the parts fitted.

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