of effort to overcome aerodynamic drag), or 2.6 m/s (9.4 km/h or 5.8 mph) on a 7% grade (2.1% of effort to overcome aerodynamic drag). 300 W for a 90 kg bike + rider at 11 m/s (40 km/h or 25 mph) on the flat (83% of effort to overcome aerodynamic drag) or 4.3 m/s (15 km/h or 9.5 mph) on a 7% grade (4.2% of effort to overcome aerodynamic drag). 165 W for a 65 kg bike + rider to go 9 m/s (32 km/h or 20 mph) on the flat (82% of effort to overcome aerodynamic drag), or 3.3 m/s (12 km/h or 7.4 mph) on a 7% grade (3.7% of effort to overcome aerodynamic drag). 285 W for a 65 kg bike + rider at 11 m/s (40 km/h or 25 mph) on the flat (87% of effort to overcome aerodynamic drag) or 5.3 m/s (19 km/h or 12 mph) on a 7% grade (6.1% of effort to overcome aerodynamic drag). Reducing the weight of the bike + rider by 1 kg would increase speed by 0.01 m/s at 9 m/s on the flat (5 seconds in a 32 km/h (20 mph), 40-kilometre (25 mile) TT). The same reduction on a 7% grade would be worth 0.04 m/s (90 kg bike + rider) to 0.07 m/s (65 kg bike + rider). If one climbed for 1 hour, saving 1 lb would gain between and – less effect for the heavier bike + rider combination (e.g., 0.06 km/h (0.04 mph) * 1 h * /mi = ). For reference, the big climbs in the Tour de France and the Giro d'Italia have the following average grades: Giro d'Italia Stelvio Pass = 7.45% over 24.3 km; Colle delle Finestre = 9.1% over 18.6 km; Colle dell'Agnello = 6.5% over 22 km; Passolanciano-Maielletta, also known as Blockhaus = 9.4% over 22 km; Plan de Corones = 10% over 5.2 km; Mortirolo = 10.4% over 12.5 km; Monte Zoncolan = 12% over 10.1 km; Tour de France Tourmalet = 7% Galibier = 7.5% Alpe D'Huez = 8.6% Mont Ventoux = 7.1%. See also Bicycle Bicycle and motorcycle dynamics Cycling power meter Cyclocomputer Outline of cycling References External links Physics-based simulation of bicycle race performance Calculate the speed and power requirements of different sprocket sizes for different Hub and Derailleur gears Cycling