AI 速览
- Even-split pacing wins flat TTs of any length; negative-split wins only when the course finishes uphill or into a headwind.
- The no-coasting rule: any second spent coasting on a TT bike is a second lost — power should never drop below 60% of FTP.
- Aero position is not free: a 5% drag reduction is worthless if the rider cannot hold the position for the final 5 km.
- Most time is lost in corners and the re-acceleration after them, not in the corner itself.
/ 01
Pacing strategy — the two options
A flat time trial is won by the rider who spends the most minutes near threshold and the fewest minutes above it. There are two valid pacing strategies. The even-split — holding a steady wattage from km 0 to the line — is the safest and almost always the fastest on a flat, windless course. The negative-split — starting 5% under target and finishing 5% over — works on uphill finishes, courses that finish into a headwind, or for riders who tend to fade. Positive-split — going out hard — almost never wins.
TT pacing strategies by course type
| Strategy | Best course | Risk profile |
|---|---|---|
| Even-split | Flat, calm conditions | Safe; optimal for most courses |
| Negative-split | Uphill or headwind finish | Demands discipline early |
| Positive-split | Almost never | Fade costs more than the early gain |
| Power-climb surge | Course with a short steep hill | Surge over FTP only on the climb |
/ 02
The no-coasting rule
On a TT bike, any second spent coasting is a second lost. The aerodynamic position is efficient enough that even at 50 km/h on a slight descent, the rider should still be producing at least 60% of FTP. The rule is mechanical: if the speed drops below the point where pedalling contributes meaningful forward motion — roughly 55–60 km/h on a flat TT bike — the rider should be pedalling. Above that speed, the marginal gain of pedalling drops below the cost of the additional drag from the pedalling motion itself.
/ 03
Aero position — the trade-off
Aero gains are real but conditional. A rider who lowers the head by three centimetres might save eight watts of drag — but only if he can sustain the position for 40 minutes. The trade-off is physiological: a more aggressive aero position restricts breathing and hip angle, reducing power output by 3–5%. The optimal position is not the most aerodynamic; it is the one where the drag reduction minus the power loss is maximised. Wind-tunnel or track data is the only way to find that point.
/ 04
Cornering and technical sections
Time is won and lost in the corners. A TT bike corners slower than a road bike — narrower bars, deeper wheels, less confidence — but the time loss comes less from the corner itself than from the re-acceleration after it. The protocol: brake early, carry speed through the apex, and start pedalling the moment the bike is upright. The mistake is braking too late — the rider loses one or two seconds in the corner and another three or four trying to get back to speed.
/ 05
The final 2 km — holding the line
The last 2 km of a time trial is where even-splits collapse. Riders who have paced correctly are now at threshold and have 90 seconds of headroom; riders who went out too hard are in deficit and losing 10–15 watts per minute. The tactic: if you are still fresh, raise the wattage by 5% — the line is close enough that the lactate will not catch you. If you are already in the red, hold the wattage; do not chase a number you cannot sustain. The instinct is always to sprint. The data says: only sprint if you can stand on the pedals within the final 200 metres.
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