How long it takes, and what is actually worth buying.
The ride
Power200 W
Distance40 km
Average gradient0%
Rider
Bike
Tyre pressure6.5 bar · 94 psi
Conditions
Wind0 km/h
40 km takes you
1:15:34
Average speed
31.8km/h
Drag area
0.340m²
Rolling
0.0069Crr
All-in weight
88.0kg
Where your 200 watts go
142W
52W
Pushing air 142 WTyres 52 WDrivetrain 6 W
What to change
3:2821.5 W
Ride in the dropsfree
Hands in the drops, back flattened. Costs nothing but the discipline to hold it.
—free
2:4517.2 W
Ride hoods, forearms levelfree
On the hoods with elbows bent until the forearms are horizontal. Free, and worth more than most wheels. Costs nothing but the discipline to hold it.
—free
25s2.8 W
Latex inner tubes
Noticeably faster than butyl for very little money. They leak overnight, so pump up before every ride.
£24£0.95/s
2:3717.6 W
Race tyre, 32 mm
The same supple race casing again, wider still. On anything but glass-smooth tarmac this is usually the fastest road tyre there is. Run them at 4.5 bar (65 psi) for this surface and your weight.
£150£0.96/s
2:2516.2 W
Race tyre, 28 mm
Same casing as the 25, wider. Usually the fastest thing you can bolt to a road bike. Run them at 5.5 bar (80 psi) for this surface and your weight.
£140£0.97/s
2:1314.8 W
Race tyre, 25 mm
Supple casing, thin tread. Fast, and you will feel every flint. Run them at 6.75 bar (98 psi) for this surface and your weight.
£130£0.98/s
1:4711.9 W
Endurance tyre, 32 mm
Wide and comfortable. On rough roads the extra width earns back more than it costs. Run them at 4.75 bar (69 psi) for this surface and your weight.
£110£1.02/s
1:208.9 W
All-round road tyre, 28 mm
The sensible middle. Reasonably fast, reasonably tough. Run them at 6 bar (87 psi) for this surface and your weight.
£90£1.12/s
How to read this. Every line is the same ride re-solved with exactly one thing changed, so the figures are yours rather than a manufacturer's. Component data in this build is seed estimates, not measurements — the shape of the answers is right, the absolute numbers will move as real test data goes in.