What determines descent speed?

Terminal descent speed is determined by the balance between gravity pulling you downhill and air resistance plus rolling resistance slowing you. Heavier riders descend faster due to higher gravitational force relative to drag.

Why do heavier riders descend faster?

Weight increases gravitational force linearly but drag stays the same (it depends on size, not weight). A 90 kg rider will reach a higher terminal speed than a 60 kg rider with the same aerodynamic profile.

How does braking affect descent?

The braking settings simulate different levels of speed management. Light braking reduces terminal speed by about 25%, moderate by 45% and heavy by 65%.

BikeCalcs

Descent Speed Calculator — Estimate Downhill Speed

Estimate safe descent speed based on gradient and conditions.

Descent Gradient

Total Weight

CdA

Crr

Braking

How We Calculate This

Terminal Descent Speed

At terminal velocity, gravity force equals drag plus rolling resistance:

Net force = m x g x gradient - Crr x m x g
Terminal speed = sqrt(2 x Net force / (air_density x CdA))

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.