Bicyclist Speed

This graph predicts bicyclist speed across a range of road slopes, for both an upright riding position and an aero tuck. Use the dials below to set power output and wind speed — the chart updates live as you adjust them.

Model assumptions:

Entry-level road bike on smooth asphalt
Sea level, standard atmosphere (20 °C)
Wind is pure head- or tailwind — no crosswind
Above 35 mph, pedaling power tapers linearly to zero at 40 mph (coasting)

Rider profile:

Height cm

Weight kg

Upright (semi-upright / hoods position)

Aero tuck

Wind Speed

− Headwind · + Tailwind

0.0 mph

Power Output

100 W

To predict the bicyclist's speed: Dial in your power output and wind speed, then read the speed for any road slope directly off the chart.

To figure out the bicyclist's power output: Measure their speed, wind speed, and road slope out on the road. Back at the chart, set the wind speed dial and nudge the power dial until the curve hits that speed at that slope — whatever the dial reads is the rider's power output.