How to choose a time trial or triathlon bike suited to your discipline?

With the growing success of time trialling and triathlon, the range of bikes has expanded greatly. Recognisable at first glance with their more or less faired profile and their extensions with remote gear controls, bikes adapted for these disciplines nonetheless cover very different realities. The choice of bike will be made according to your level of practice and your budget.

What is time trialling / triathlon?

Gaining more and more followers, time trialling and triathlon are two disciplines in their own right, characterised by a common point: a solo effort generally taking place on a fairly flat course, where you battle as much against other competitors as against the clock.

Bikes designed for this type of discipline are therefore highly streamlined and aerodynamic. They are designed and engineered to maximise air penetration through riding position, thus converting every watt into pure speed. The choice of bike will be made according to your discipline, your level and your budget.

The characteristics of TT/Triathlon bikes

In time trialling/triathlon, carbon now rightfully dominates. The various manufacturing processes make it possible to produce frames that are both high-performing, aerodynamic and lightweight, even if these bikes are heavier than standard road bikes. Above all, these models are much stiffer.

The handling and air penetration of these bikes are systematically studied in wind tunnels. Notably, oversized tubes and wider forks are used to reduce turbulence. The seat tube angle is more pronounced while the seatpost and the handlebar are lower. The top tube is very often sloping and extensions complete the whole setup to accentuate the rider's aerodynamic position. Finally, component integration is pushed to its maximum: stem, seatpost, brake callipers…

It should be noted that certain faired models, or those with too forward a position or excessively long extensions, are reserved for triathlon use and cannot therefore be used in time trials as they do not comply with UCI regulations.

Which frame for my discipline?

For occasional use or for beginners, an aluminium frame is the way to go. Equipment has evolved to offer high-performing bikes at an affordable price with this material.
More dedicated competitors will opt for a lighter and stiffer carbon frame in pursuit of performance.

Whatever the material, particular attention must be paid to choosing the right frame size, as the top tube is shorter than on a road bike and the bottom bracket is raised, which reduces the seat tube dimension.

Finally, if you are planning to take part in competitions with a hilly or mountainous profile, it is preferable to opt for a less specialised model, at the risk of having a truly terrible time on the climbs. An aero or mountain-profile road bike will therefore be a far more relevant choice, even if it means installing extensions separately to benefit from the performance of the aero position on the flatter sections.

The importance of wheels

In these disciplines, the choice of wheels is crucial to optimise the whole setup and make the most of the frame's characteristics. This choice will be made primarily according to the courses ridden and the weather conditions.

Most time trial specialists and triathletes have several pairs of wheels in order to adapt to these two factors.

• Low-profile rim: a low-profile and lightweight rim will be chosen, guaranteeing reactive climbing and explosive accelerations for mountain use.
• Higher and profiled rim: a higher and profiled rim is preferred on flat or hilly courses for its performance in terms of kinetic energy and aerodynamics
• Lenticular wheel: the most ambitious riders can use a lenticular wheel if weather conditions permit (no wind). These wheels are however demanding to handle, both physically and technically, and therefore require a good level of mastery.