Track cycling at the Paris Olympics: A complete guide

Track cyclists ride on a fixed gear bike, which doesn't have a freewheel in the rear hub. Instead, the single sprocket at the rear is attached directly to the rear wheel. This allows good power transfer for explosive acceleration, but means that the rider must pedal while the bike is moving. It also means that braking is via the rider's legs rather than having a mechanical brake.

A derny is a motor-powered bike. Riders ride behind the derny in the first few laps of the keirin event as they gather speed. The derny then peels off and the riders compete against each other.

Dernys used to be powered by a small petrol motor with a fuel tank over the front wheel, but modern dernys are increasingly powered by an electric motor. The derny rider will sit upright to help lower wind resistance for the riders behind.

They can travel up to 90km/h, but races rarely exceed 80km/h. 

A tubular tyre is formed as a continuous roll of casing fabric, like a circular sausage, with the inside edges of the tyre sewn together. There's an inner tube enclosed in the casing. The tyre is glued to the wheel rim, which has a shallow dish rather than the more standard clincher wheel's raised rims.

Tubular tyres used to be popular with road racing cyclists, but they've largely been replaced by tubeless clinchers. They're still used on the track due to their ability to hold high pressures, but some nations have begun using tubeless tyres and inner tubes on the track too.

While on roads, wider tyres at lower pressures are faster, a narrow tyre at high pressure is still faster on a track due to the smooth surface. Thus track bike tyres are typically run at over 100psi, in some cases up to 200psi.

A disc wheel is a wheel which has enclosed sides, rather than using spokes. It's often used as a rear wheel for time trial bikes, due to its aerodynamic qualities, although disc wheels are in general heavier than spoked wheels, as well as more expensive. It's rare for cyclists to use a disc wheel at the front because wind catching it can make it more difficult to steer safely, but Wout van Aert did use one in the time trial in Paris. 

Indoors, where wind isn't an issue, disc wheels are more commonly used at the front as well as at the rear. 

A trispoke wheel has three wide carbon spokes between its rim and hub. It's more manoeuvrable than a disc wheel, but more aero than a spoked wheel and typically used as the front wheel of a track bike.

Not all track bikes are equipped with front wheels with three spokes; wheels with four or more spokes are also often used.

Track cyclists can achieve peak speeds in sprint and team pursuit events of around 80km/h. The men's world record for the team pursuit is 3:42.032, which is an average of almost 65km/h (40.3mph) from a standing start.

Since they are fixed-gear bikes, riders of track bikes can decelerate just by lowering their pedalling cadence, so there's no need for brakes. The track is flat and there are no obstacles to prevent a controlled slowing down without braking. 

Track cycling and road racing are very different events, requiring different rider capabilities. The Tour de France takes place over 3,000km-plus over 21 days of racing. 

In contrast, track events are all under 100km, most significantly so, and some are as short as 200 metres. They're on the flat too, so a rider doesn't need to be good at climbing, unlike Tour de France winners. Track cyclists tend to be powerfully built and good at anaerobic exercise, whereas Tour de France winners are lean and have high aerobic capacity.

There is occasionally some crossover between road and track cyclists though. Filippo Ganna is an Italian road cyclist who races time trials, has raced the Tour de France, and will compete in the Team Pursuit in Paris. He will almost certainly never win the Tour de France though, as his skill is in races against the clock, not racing up mountains. 

However, Bradley Wiggins and Geraint Thomas, both Team GB athletes in recent years on the track, have won the Tour de France. Both raced on the track to great success before refocussing on the road. Wiggins had a four-year gap, winning his last Olympic track medal in 2008 and the Tour de France in 2012. Thomas's gap was six years, winning in 2012 on the track and 2018 in France.

Despite their mechanical simplicity, Olympic track bikes are very expensive. That's due to the substantial R&D that goes into developing a top-fight track bike and the small market for Olympic-level track bikes. There's a constant arms race to make Olympic track bikes more aerodynamic and better performing.

The Team GB Hope-Lotus track bike frameset alone costs around £25,000, depending on the spec. The most expensive track bike is currently the Japanese V-Izu TCM-2, which costs over £100,000 if you tried to buy one. Most track riders have their bikes supplied by their national teams, so they're not paying for them.

It's only recently that track bikes have become wide, with the Hope-Lotus bike the forerunner. Previously, they were very narrow, but Team GB's research showed that the frame was more aerodynamic if the fork blades and seatstays were kept away from the turbulent air caused by the wheel and instead placed in line with the rider's legs. It's a trend since adopted by other countries for their track bikes. 

There are other odd-looking aerodynamic features, such as the double seatpost on the French team's Look P24.

Some track bikes have their drivetrains on the left, rather than the right side of the bike. Pioneered by the US team at the Rio games, the thinking is that since track bikes always turn to the left, the left side gearing is more sheltered by the front wheel and so more aerodynamic. 

Since they're ridden on the flat, there's no need for lower ratios to tackle hills. Track riders train to deliver power efficiently at a range of cadences. Many track events only involve competition once the rider is moving, so there's little need for a low gear to get started either.

Drafting occurs where a following rider rides close enough to the rider in front to benefit from their slipstream, thus saving a lot of energy - estimates range up to 50%. 

It's a common tactic in all cycling, but particularly in track events such as the team pursuit, where riders will train to ride very close behind each other to maximise the aerodynamic gain.

Bikes designed for pursuit events, where riders keep up high speeds for longer distances, will be equipped with bar extensions. Once they've accelerated, when they'll use the wider bars, riders will use the extensions. These keep them low and tucked on the bike, for optimum aerodynamics.

Bikes used for sprints don't have extensions, since riders are putting in high effort for a shorter distance and so need to be able to pull against the handlebars, rather than getting tucked.

A handsling is where one rider grabs another's hand behind them and pulls them forward. It's a feature of the Madison event, where pairs of riders hand over racing between them, and allows the lead rider to impart their momentum to the follower, making for a faster handover.

Aerodynamics in track cycling extends from the design of bikes to the clothing worn. It's been found that ridged fabrics can be more aerodynamic than smooth ones. 

Ridges and sawtooth trailing edges now extend to track bike frames too, in pursuit of optimum aerodynamics. 

A track stand is where a rider keeps their bike stationary by balancing their bike without putting a foot down. They may keep their bike completely stationary or, since the bike gearing is fixed, rock it slightly backwards and forwards. 

It's used in individual sprint races to try to gain an advantage over an opponent and force them to lead out so that the second rider can slipstream them once the sprint phase starts. 

On a typical Olympic length 250m track, the banking will rise to around 42 degrees. It will be greater on a shorter track, and less on a longer track. 

As with all bikes used in competition, track bikes are subject to the UCI's 6.8kg minimum weight limit. Since they're mechanically simple and usually built of carbon fibre, many will weigh around this value. 

Several nations are experimenting with 3D-printed metal track bike frames though, which may increase the weight somewhat.

A lot. There's a video of German track cyclist Robert Förstemann generating enough power for over three minutes - around 700 watts - to toast a slice of bread. In his prime, Chris Hoy could put out 2,500 watts and 700Nm torque. A good benchmark for most male track sprinters is around 25 watts per kilo, and 20 watts per kilo for women. 

The black line, on the Saint-Quentin-en-Yvelines Velodrome is measured at 250 metres (273.4 yards) long, as is Olympic standard. 

The red line, which sits 90cm outward of the black line, is 5.7m longer for a full lap of the velodrome. 

On the very inside edge of the track is a flat section. Usually unboarded and made of concrete, it's used to get started.

Next is a light blue line, dubbed the 'Côte d'Azur', which indicates the inside edge of the track. 20cm above this is a black line, which denotes the length of the track and is followed as much as possible by riders to keep the distance they have to travel to a minimum.

At 90cm above the black line is a red line. Called the sprinter's line, it's used in sprint competitions. As long as a lead rider is between the black and red lines, another rider must pass above them. While being passed, the leader can't move above the red line and must stay within the two lines. 

Finally, there's a blue line further up the track, which is used in the Madison. Every not-in-play rider from each pairing must remain above this so that they're not in the way of competing riders.

Both are part of the same group. As with many performance motor sport brands, such as Red Bull and McLaren, Lotus Group includes an engineering consultancy, which developed the Hope-Lotus bike alongside British Cycling.

Hope Tech is a cycling brand primarily focused on mountain bikes and components, which is responsible for building the frameset.

As with their bikes and clothing, aero is everything for track cyclists. An enclosed helmet with a long tail and a visor will be more aerodynamic than a standard vented road helmet.

When cycling, one of the biggest obstacles that cyclists have to overcome is the air. It's for this reason that aerodynamic bikes, helmets and clothing is so highly sought after, and riders often go to altitude for world record attempts. 

The higher the air density, the more air they have to push out of the way, and that takes more power. Lower air density means there's less air to overcome, which requires less power, or equals faster speeds for an equivalent power. 

After a thunderstorm, air pressure is significantly reduced, which means low air pressure, less resistance to overcome, in turn higher speeds, and therefore faster times!

Inside the velodrome it is hot, and while riding body temperatures can rocket which has a detrimental impact on performance. In order to counteract this, riders will warm up while wearing vest filled with cooling gel. This loosens up the muscles while keeping core temperatures from getting too high.