How do Tour de France time trials work?
While many cycling fans will be well versed in the nuances of the time trial, the Tour de France is a race that draws countless new fans to the race every year. The race format of the Tour de France is also pretty straightforward, but for the pivotal time trial stages riders are forced to leave behind the team support and race against the clock, alone. TTs are also divisive among cycling fans, as many spectators and pundits consider the solo discipline boring when compared with the tactical thrills of mountain racing and sprint trains, while the cycling purists often see the TT as the ultimate display of a riders ability on the bike. This years Tour de France route features two time trials totalling 58km at key points, the first of which comes on stage five (27.2km-long) before the decisive TT on the penultimate stage, day 20 (30.8km). Geraint Thomas (Image credit: Getty)  Time trials actually exist in a number of different sports, from cycling to cross country skiiing and motorsports. A TT is basically a timed race from one point to another, but in cycling there are two main types - the individual time trial and the team time trial. The individual time trial, which make up both of the Tour de France TTs this year, see each rider compete alone against the clock without the benefit of slipstreaming, while a TTT sees a team of riders (from two to 10) race as a unit to complete the course in the fastest time. Time trials can either be raced as a standalone event, such as the World Championships TT or the once-prestigious Chrono des Nations event, or as part of a multi-day stage race like the Tour de France. In a stage race, a time trial will result in an individual stage winner being crowned, while each riders time will also be added to their overall general classification time, which will decide the winner after the final stage of the multi-stage event. Time trial bike (Image credit: Getty Images)  There is one major detail you might noticed watching your first Tour de France time trial - the bikes. A time trial bike is quite a striking change from the traditional road bikes were used to seeing out on the road, as theyre designed for pure aerodynamics to slice through the wind as quickly as possible. To make them as quick as can be, time trial bikes are often heavier, trickier to handle and less comfortable than a traditional road bike, but by far the biggest difference is the riding position. Geraint Thomas's Tour de France-winning road bike (Image credit: Getty Images)  TT bikes come with special out-front handlebars that put rider in a narrow tucked position to reduce their aerodynamic drag, while they also have a base bar, which riders use to brake and corner more comfortably. According to our own research, a time trial bike can be as much as 87 watts faster than a road bike at 40kph. Wheels are also a key choice for a time trialist, as most riders while use a carbon disc wheel on the rear of their bike and a very deep section carbon rim on the front. These wheels are much more aerodynamic than the wheels used on a normal road stage of the Tour, but are also less comfortable and makes the bike unstable in strong winds. Time trial riders vs climbers  Filippo Ganna at the 2021 Giro d'Italia (Image credit: Tim De Waele/Getty Images)  While time trials are always held under the same rules, the terrain TT courses cover can vary greatly, meaning each event may suit a different kind of rider. For the flat and fast TT courses, its a case of pure power and aerodynamic ability, which means heavier riders like world champion Filippo Ganna (Ineos Grenadiers), who sits at around 82kg, or Jumbo-Vismas Edoardo Affini (80kg). But often time triallists can blur the lines between pure power and climbing ability, most notably the likes of Geraint Thomas, Rohan Dennis (both Ineos) and Primo Rogli (Jumbo-Visma), who are amongst the strongest climbers in the world while still being able to deliver huge power on the flats. In recent years however, weve seen the resurgence of the uphill time trial, with race organisers opting to challenge a riders versatility, splitting courses between rapid, flat sections and tough mountain climbs to the line, like stage 20 of the 2020 Tour de France on La Planche des Belles Filles. These stages often favour riders who can maintain a high watts per kilogram (w/kg) rather than pure power when pedalling, as lighter riders tend to climb faster. For this reason, pure climbers often have the chance to show their ability against the clock, as was demonstrated by Rigberto Urn (EF Education-Nippo) in the 2021 Tour de Suisse, where he won the stage seven ITT, which featured a mountain climb and then descent, with the likes of Julian Alaphippe (Deceuninck - Quick-Step) and Richard Carapaz (Ineos Grenadiers) both finishing high up in the rankings. This varying nature of time trials are what make them so pivotal in a Grand Tour like the Tour de France, as strong time trialists often use these stages to gain general classification time back on the lighter, pure climbers, who traditionally have the advantage on the mountain stages and aim to limit their losses in TTs. The first of the two Tour time trials this year falls on stage five, a 27.2km ride from Change to Laval (Espace Mayenne) in north western France. Profile for Tour de France 2021 stage five (Image credit: ASO)  This stages profile can best be described as lumpy, as the course opens with a 1km-long climb, followed by a number of rolling hills through the middle section. The final third of the stage is almost entirely flat, with a 300 metre ascent around 2km from the finish line. There are also a number of sharp 90-degree turns spread through-out the course with a very technical finish in Laval, which could be a risk for the riders who dont spend much time on their time trial bikes. >>> Tour de France standings: The latest results from the French Grand Tour  Emulating the 2020 Tour de France, this years race once again features a time trial on the penultimate day, which means the GC will be decided on stage 20 before the processional sprint stage in Paris on day 21. Stage 20 from Libourne to Saint-Emilion is a 30.8km-long test on a gradually rising course, with a 500m climb mid-way through the stage and an ascent to the finish. Tour de France 2021 stage 20 profile (Image credit: ASO)  With plenty of long straights and a few sharp turns scattered through the stage, this course is likely to suit a pure time trialist for the stage win, but will also be a key moment for the general classification contenders to decide the overall result.