How to use this calculator
- Enter engine torque. Use the torque the clutch must hold.
- Enter clutch load. Set clamp force from pressure plate data.
- Enter friction geometry. Set friction coefficient, mean radius and surface count.
- Review margin. Compare design torque capacity with engine torque.
How it works
The simple clutch model is torque = clamp force x mu x mean radius x friction surfaces. The design capacity divides that raw value by the entered safety factor.
Pair this with wheel torque and driveshaft critical speed for drivetrain checks.
Worked example
Verified against the live calculator
A clutch with 9000 N clamp force, 0.32 friction coefficient, 105 mm mean radius and two friction surfaces has about 605 N*m raw holding torque before applying safety factor.
Frequently asked questions
How is clutch torque capacity calculated?
The calculator multiplies clamp force, friction coefficient, mean friction radius and the number of friction surfaces.
What are friction surfaces?
A single-disc clutch commonly has two working friction interfaces. Multi-disc clutches have more.
Why include a safety factor?
The safety factor turns raw capacity into a design capacity for comparison with engine torque.
Does this predict clutch life?
No. Life and slip behavior also depend on heat, lining material, engagement style, flywheel condition and pressure distribution.
Method & assumptions
- Uses a simple mean-radius friction model.
- Temperature, pressure distribution, facing wear, break-in, release travel and shock load are not modeled.