Bike power ↔ speed
See what speed your power gives on the flat or a climb, or how many watts a target speed takes.
Rider and road
Advanced: drag and tyres
CdA: about 0.22–0.26 for a good aero position, 0.30 for a typical age-grouper on a tri bike, 0.35–0.40 on the hoods of a road bike. Crr: 0.003 for fast race tyres, 0.004 for good road tyres, 0.006+ for rough roads.
Result
At 200 W on other gradients
| Gradient | Speed |
|---|---|
| -4% | 54.7 km/h |
| -2% | 45.1 km/h |
| 0% | 34.6 km/h |
| +2% | 24.7 km/h |
| +4% | 17.4 km/h |
| +6% | 12.8 km/h |
| +8% | 10.0 km/h |
| +10% | 8.2 km/h |
Time at this speed
| Distance | Time |
|---|---|
| 20 km | 0:34:39 |
| 40 km | 1:09:17 |
| 90 km | 2:35:53 |
| 180 km | 5:11:47 |
A physics model with no wind, at sea level. Real speed depends a lot on your actual drag (CdA), so treat this as a rough guide. Descents are capped at 70 km/h.
How it works
Power = air drag + rolling resistance + gravity, times speed, divided by drivetrain efficiency. This model was validated against on-road power-meter data (Martin et al. 1998).
Why your numbers may differ
Drag (CdA) varies a lot between riders and positions, and wind changes everything. Treat results as a guide. More in the methodology.