Track Cycling Explained: The Motorbike, and Why Sprinters Ride Backwards

The keirin’s motorbike is the whole event

To a new viewer the keirin looks like a mistake — a small motorbike leading a bicycle race, then leaving.

Cycling’s other Olympic disciplines are covered in BMX rules and scoring.

The derny is a motorised pacer. It takes the field from roughly 30km/h up past 50km/h, and then pulls off with about two and a half laps to go. Riders must remain behind it until it goes.

Its purpose is to remove the thing that would otherwise decide the race: the acceleration. Without a pacer, a keirin would be won by whoever could get up to speed best from a standing start, and the final laps would be a procession.

The derny hands every rider the same speed at the same moment. What remains to be contested is position — and position behind a pacer, in a fixed order determined by draw, is the entire tactical content of the event.

The match sprint is three laps and one race

A sprint is contested over three laps, and for much of it riders may be barely moving, sometimes balancing stationary.

That is not showmanship. In cycling, the rider in front does the work, punching a hole in the air for whoever sits behind. Leading early in a three-lap race is a straightforward way to lose it.

So both riders try to be second, until the moment being second becomes worse than being first. The slow-motion phase is a negotiation about who is forced to start the sprint — and the real race lasts one lap, sometimes less.

The format has not failed. It has produced exactly the contest it describes: first over the line after three laps, with no rule requiring anyone to hurry before then.

Team pursuit: four riders, three times

Speed skating runs the same sacrifice on ice, with three skaters and the time taken on the last — see speed skating rules.

This is the rule that produces the sport’s most interesting sacrifice.

Two teams of four start on opposite sides of the track over 4km. They ride in a line, rotating the lead about every half lap, because the riders behind are sheltered.

The team’s time is taken when the third rider crosses the line.

Four start; three count. A team may lose one rider entirely without penalty.

The consequence is a deliberate tactic. A squad can ride its weakest rider into complete exhaustion — extracting one final turn on the front — and then let them drift off the back, because their time is irrelevant. The remaining three, having been sheltered by that effort, go faster than four riders would have.

It is entirely legal, openly planned, and rational. The rule says three, so teams optimise for three.

And the clock is not the only way to win: if one team catches the other, the race ends.

The track itself is part of the rule

Nothing above works on a flat surface, and the banking is not decoration.

A velodrome’s bends are steeply banked so that riders travelling at speed are held against the surface rather than thrown off it. The faster you go, the higher up the track you can ride — and the higher line is longer.

That single geometric fact underwrites every tactic on this page. A rider sitting high on the banking has further to travel but can convert height into speed by dropping down the slope at the right moment. Attacking from above is a genuine accelerant, not just a change of position.

It is also why lap counts differ between events at different venues. Distances are fixed — 4km for a team pursuit — but a 250m track and a 333m track cover them in different numbers of laps, so the same race is a different rhythm depending where it is held.

Why these formats look arbitrary and are not

Triathlon wants the opposite of all this and has to legislate the slipstream away — see triathlon’s drafting rules.

Each of these events was designed around a constraint that is invisible if you do not know about it.

The keirin exists because acceleration would otherwise decide a sprint. The match sprint’s crawling phase exists because leading costs energy. The team pursuit’s sacrifice exists because the rule counts three of four.

Track cycling is unusually honest about this. It does not pretend the aerodynamics are not determinative; it builds formats around them, and then lets riders exploit the results.

Compare cycling’s own 3km rule on the road, which likewise legislates around a physical reality — a bunch sprint being dangerous — rather than asking riders to behave differently inside it. The sport consistently changes the incentive rather than appealing to the athlete.

More rulebook coverage is in rules and techniques, and more on how governing bodies design competition in how sport is run.