mph
170
watts
2.5
w/kg
Gravity
0 watts
%
lbs
lbs
Gravity
- Grade: Enter a positive value for uphill, negative value for downhill.
- Rider Weight: Weight when wearing full a kit including shoes.
- Bike Weight: Include all mounts, saddle bags, etc.
Fg = g * sin(arctan(slope)) * (M + m)
- g = gravitational acceleration (standard value of 9.80665 m/s2)
- slope = gradient (%)
- M = weight of the rider (kg)
- m = weight the bike (kg)
Drag
141 watts
mph
ft
Drag
- Elevation: Refers to elevation above sea level at point in time of the calculation (not total elevation gain of a climb). A higher elevation will result in a lower air density requiring less watts for a given speed.
- Wind: Enter a positive wind value for headwind and a negative value for tailwind.
- Riding Position: Hoods position is also known as "relaxed hoods", where arms are
slightly bent (ie, not "aero hoods").
CdA estimated values:1
tops: 0.408
hoods: 0.324
drops: 0.307
aerobars: 0.2914 - Wheelset: Aero wheelset option reduces CdA value by 3%, super aero wheelset reduces CdA by 5%.2
- 1 High-performance Cycling, Asker E. Jeukendrup (2002)
- 2 Cyclist.co.uk
Fd = 0.5 * Cd * A * ρ * (v + w)²
- Cd = drag coefficient
- A = frontal area
- ρ = air density
- v = speed (meters per second)
- w = wind speed (meters per second)
Rolling Resitance
22 watts
Rolling resistance
- Tire: Coefficient of rolling resistance (Crr) values are based on 100psi tire
pressure for road, 36psi for gravel. All values are assuming a paved road surface. Using the
advanced mode you can enter a specific Crr value.
Crr values by tire:1
Continental Grand Prix 5000: 0.00321
Continental Gatorskin: 0.00606
Specialized Pathfinder Pro2 Bliss: 0.00722
Vittoria Terreno Dry G+ 2.0: 0.00809
Fr = g * cos(arctan(slope)) * (M + m) * Crr
- g = gravitational acceleration (standard value of 9.80665 m/s2)
- slope = gradient (%)
- M = weight of the rider (kg)
- m = weight the bike (kg)
- Crr = coefficient of rolling resitance
Drivetrain Efficiency
7 watts
Drivetrain Efficiency
- Chain: 3% power loss for well lubricated chain, 4% loss for poorly lubricated chain.1
- Derailleur Pulleys: 2% power loss for steel bushings, 1.5% for steel bearings, 1% for ceramic bearings, 0.5% for ceramic bearings with oversized cogs.2
- Pedals and Bottom Bracket: There is power loss from bearings in the bottom bracket and pedals but in most cases it is less than 0.3% so we have omitted from our model.
De = (1 - loss)
- loss = percentage loss in power from drivetrain