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Tour de France riders will take on the second individual time trial of this year’s race on Saturday (23rd July 2022), a 40.7km (25.3-mile) flat course from Lacapelle-Marival to Rocamadour, so they’ll be swapping from road bikes to specialist TT bikes for the day.
Pic © SWpix.com (t-a Photography Hub Ltd)
Time trial performance could be very important to the GC (General Classification) outcome with just the largely ceremonial final stage to follow, so let’s check out the tech that the riders will use to shave the seconds.
Geometry
Time trial bikes tend to have steeper frame angles than road bikes, the idea being to pivot the rider further forward around the bottom bracket for a more aerodynamic, flat-backed riding position.
Bike geometry 101: Learn why frame angles & trail matter
Pinarello’s new Bolide F time trial bike, for instance, as used by Ineos Grenadiers, has a 77° seat angle whereas the brand’s Dogma F road bike’s seat angle is between 72° and 74.4°, depending on the frame size.
Pinarello announces Bolide F as its “fastest bike ever”
A time trial bike’s head tube is also much shorter, as a rule. It’s 96mm on a 52cm Pinarello Bolide F compared with 123mm on an 53cm Dogma F.
The front end of most high-end time trial bikes is kept low by a stem that is integrated into the frame. Again, the Pinarello Bolide F (above) is a good example, as is the new Colnago TT1 (below).
If a rider needs a higher front end, that’s usually achieved through the use of a tall stack of spacers.
Colnago has gone for a very short head tube and a tall stack of spacers under each elbow rest to get the correct position.
Check out Colnago’s newly updated TT1
It says that this approach offers less drag than “a more voluminous frame”.
Frame tubes
Time trial bikes come with frame tubes and features that use airfoil shaping to slip through the air with the minimum of drag.
Merida’s Time Warp TT is typical of the genre in its use of a super-deep head tube and a seat tube that is cut away around the leading edge of the rear wheel. The seat tube is shaped for aerodynamics too, as are the seatstays which join the seat tube low to minimise the bike’s frontal area.
The down tube is dropped and cut away around the trailing edge of the front wheel in order to manage airflow in that area, while the fork legs are narrow and deep too.
It depends on the brand but frame tube profiles are often cut off square at the back rather than trailing away gradually. This is designed to maintain most of the aero performance of a deeper tube while saving weight and staying with UCI equipment rules.
Virtually all brands say that their time trial bikes have been designed using CFD (computational fluid dynamics) software and validated in the wind tunnel.
Pinarello added disc brakes to the latest version of the Bolide and, all other things being equal, that would have increased drag by 1.4%.
“This deficiency was recovered during the development process, thanks to a complete re-design of the seat tube, seat post, top stays [seatstays], and chainstays, which counter-balanced the increased aerodynamic drag of the disc brake to create an aerodynamically equivalent bike and rider system,” Pinarello said.
Hidden components
Designers hide many components from the wind to improve aerodynamic efficiency. Fork crowns and stems are typically incorporated into a bike’s existing silhouette so as not to increase the frontal area.
Giant shelters the front brake of its Trinity time trial bike behind the fork, for example.
The rear brake is located on the underside of the chainstays, just behind the bottom bracket.
The Shimano Di2 Junction A box on the BikeExchange-Jayco bikes is zip-tied to the underside of the saddle.
On this bike, it’s tucked in the end of the aerobar.
Where used, water bottles and cages are designed to integrate almost seamlessly with the frame.
You’ll see virtually no external cables or brake hoses on a pro-level time trial bike. Everything is hidden away so that it can’t disturb the airflow. Many top-level TT bikes, such as Colnago’s TT1, are designed only for electronic shifting. The complicated routing required would be unsuitable for traditional cables.
Aerobars
The idea of aerobars is that they allow the rider to achieve an aerodynamically efficient position that has in many cases been honed in the wind tunnel, while being comfortable enough to stay in that position for the duration of the stage or race.
The horizontal distance between the centre of the bottom bracket and the tips of the extensions (including controls/levers) must not be more than 75cm in most cases (although it can be up to 85cm for riders 1.90m and taller – so Superman positions, with arms stretched out ahead of the rider, are not allowed.
Most riders use standard bars that are adjusted to suit their dimensions. The maximum dimension of the cross-section of each extension is 4cm, but they can be set further forward or back to get the right position.
The height of the armrests and extensions can usually be set with the use of spacers.
Most pro riders these days tend to go for a setup with their forearms angled upwards rather than horizontal, believing it helps in terms of both comfort and speed.
UCI rules state, “The handlebar extensions plus any accessories (controls, levers, etc and all their mounting accessories) must be within ±10 cm with a tolerance of 5mm from the level defined by the middle of the elbow/forearm supports. Elbow rest pads must not be taken into account during the measurement.”
A lot of riders are right on the limit these days.
“The maximum inclination of each elbow rest (measured on the support surface of the arm) is 15°,” says the UCI.
Ineos Grenadiers use custom 3D-printed bar extensions. These are created by scanning each rider’s forearms in the most aerodynamic position and then 3D printing them in titanium.
The idea is that this allows each athlete to ride with no gap between the bar extensions and their forearms to keep drag to a minimum.
3D-printing titanium takes a long time but complex components can be made using this technique, Pinarello doesn’t need to invest in new manufacturing tools, and the design can be changed easily to suit different riders.
Consumers can now have bar extensions custom-made too. How much? It’ll depend on the result of your preliminary assessment, but it’s not going to be cheap.
Grip
You see grip tape used extensively on base bars, shifters and aero extensions to stop riders’ hands from slipping, particularly when sweaty.
On this Team BikeExchange-Jayco bike, foam cushioning has been added at the end of the extensions for comfort and a firmer handhold.
The material covering the topside of the aero extensions on UAE Team Emirates bikes is the CPC polymer that Prologo uses on some of its saddles. It is designed to provide grip and damp vibration.
Shifters
Multiple shifters are possible with the electronic systems that all pro teams use.
This means that riders can change gear while their hands are positioned at the ends of the aero extensions – as they are most of the time – and also from the base bar when they’re riding out of the saddle or cornering.
This UAE Colnago TT1 has Campagnolo EPS buttons on the underside of his aero extensions…
…and also at the ends of the base bar.
Some riders just have one button on each of their aero extensions, one to move the rear derailleur inward and the other to move it outward. On a fast TT course, there’s rarely any need to change between chainrings. This rider is using Shimano’s R9160 Di2 Remote Triathlon Shifters.
As well as the buttons (above) Campagnolo offers ’Back to Zero position’ bar end controls. One lever controls each derailleur. You push the lever up to move the chain in one direction and down to move it the other. The lever always returns to its central position.
Wheels
If it’s a flat course like Stage 20 of the 2022 Tour de France, most riders will go with a disc wheel at the rear. Disc wheels weigh more than standard spoked wheels – this Vision Metron TFW isn’t heavy by disc standards but it’s still 970g. The advantage, though, is their amazing aerodynamic efficiency.
You’ll see deep-section wheels up front, the only exception being in blustery conditions when more depth can make for difficult handling.
Many teams use tri-spoke or 4-spoke front wheels. This is a Cadex 4-spoke Aero Tubular wheel, for instance. Again, it’s not the lightest wheel in the world – it has a claimed weight of 760g – but the spokes are shaped specifically to reduce drag and that’s a more important consideration.
Gearing
Riders tend to push bigger gears on their time trial bike than they do on their standard road bike. Many find it possible to produce more power this way, and they don’t need to be ready to respond to unexpected accelerations like they do when riding in a group.
The gears chosen will depend to some degree on the stage profile, but 56-tooth and 58-tooth outer chainrings are common on flatter courses.
A 56/44-tooth chainset is fitted on the UAE bike (above) which is by no means unusual.
And this is a 58/46-tooth chainset on a BikeExchange-Jayco bike.
Saddle
Some riders use a regular saddle on their time trial bike. Geraint Thomas, for example, tends to use a Fizik Arione, as he does on his road bike (you can just about see the back of it in the picture below). He knows what he likes and he’s sticking with it!
Other riders switch saddles, though, for ones that are designed specifically for time trialling.
The geometry of a time trial bike and the low riding position adopted on aerobars means that many riders feel more comfortable with a saddle that has deeper padding at the front end. Many time trial saddles have a shorter than normal nose so as not to restrict movement.
This is Filippo Ganna’s bike fitted with a Fizik Ares, which is a popular choice with Ineos Grenadiers even though the model was dropped from the lineup several years ago.
This UAE Team Emirates rider is using a Prologo Dimension Tri with a recess that’s designed to reduce pressure when in an aero position while the CPC texture on the top is designed to stop the rider from gradually creeping forward while pedalling, avoiding the need for periodic repositioning.
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