Classical Physics Speed / Power Calculator

Adjust real-world parameters (rider size, rolling resistance, gradient, bike + wheel mass) to estimate speed, power, or W/kg using the same classical physics model used by ZwiftGopher.

Inputs
Use negative values for descents.
Typical road values: 0.003–0.006
Fixed to sea-level density.
Comparison rider

Choose whether the comparison rider should match the primary rider's speed or power.

Results
Calculated Speed
40.0
km/h
Calculated Power
250
watts
Calculated W/kg
3.3
W/kg
Estimated CdA
0.0
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