Factor officially launches the One, the "fastest UCI-legal road bike in the world"

Factor has launched the new One aero race bike, claimed to be the “fastest UCI-legal road bike in the world”.

Formerly known as the ‘Prototype’, which made its racing debut under select Israel–Premier Tech riders at the 2025 Critérium du Dauphiné and Tour de France, the bike draws inspiration from track bike aerodynamics, and the latest rider position and equipment trends.

Factor also says it has exploited the latest UCI tech regulations, with wind-tunnel testing showing it to be up to 22 per cent faster than a Specialized Tarmac SL8 and around 15 per cent more efficient than a 2024 Cervélo S5. 

However, while these claims are headline-making, Factor insists the main improvements for the rider are seen in the geometry and fit.

• Read more: Factor's unreleased aero bike is even more eye-catching in the flesh

Designed for the latest fit trends

Factor says the One is designed around the latest rider-fit and component-choice trends, which results in a no-compromise system for racing speed.

David Millar, ex-racer and TV commentator installed this year as Factor’s brand director, explains that, since his racing days, bike design has continued to follow the same basic formula, with components changing to suit the rider.

“With the One, it’s different,” he says. “It’s designed with these adaptations in mind. Racers are choosing longer stems, inline seatposts and shorter cranks to improve their performance and efficiency.”

Millar uses the example of Mark Cavendish and Jonathan Milan – riders of opposing statures – whereby their bike-size needs are very different. However, with bike wheels currently at the fixed 29in / 700c size, a rider’s weight distribution and fit adaptations are very different with current ‘standard’ frame geometries.

Millar says the One fixes this disparity, thanks to the frame’s longer effective reach compared to a typical layout. This is said to shorten the effective stem lengths riders will require by 20mm, while still getting the handlebar drops where needed.

The seat tube angle is also far steeper than typical, at around 76 degrees, which pitches the rider forward relative to the bottom bracket and opens the hip angle for more efficient power transfer through the cranks. 

This means the rider’s effective saddle-mounting point is 25mm forward compared to the Ostro VAM, so a 30mm-setback seatpost yields a similar centred saddle position as an Ostro VAM with an inline seatpost (an inline post remains available for those who need or want one).

Rob Gitelis, Factor’s CEO, says it was former rider Alex Dowsett who first posited a bike designed for the job of breakaway and leadout efficiency – a Hanzo time trial bike for the road.

He claims the One’s design effectively meets that brief, while satisfying the UCI-mandated minimum setback of 0mm from the tip of the saddle to the bottom bracket centreline, and keeping the saddle rails supported properly.

Optimised handling geometry

Factor has also increased the bottom bracket drop – partly compensating for the use of wider tyres and the trend towards shorter crank lengths – which should provide more stable handling on descents. 

This, in combination with the modified rider-weight distribution, is said to help avoid the tendency to overload the front wheel (thereby avoiding under-loading the rear wheel) and maintain traction. 

The added confidence this drives should see riders adopt a more efficient and natural-feeling position when descending, improving overall speed. Millar (who is 1.92m tall) says he set a KOM on the descent of Els Angels near his home in Girona, Spain, aboard the One, without specifically setting out to do so. 

Factor also claims the steep head tube angle is preferred by the vast majority of smaller riders it has worked with. 

On typical smaller-size frames, head angles have needed to be slackened and fork rakes increased to preserve essential toe clearance, but this can lead to 'front wheel flop' – essentially, slow and unbalanced responses through the front end.

The cockpit is similar in overall design to the Colnago Y1Rs’, with a rising V-shape taking the place of a typical stem (Factor refers to this shape as a 'gullwing'). The Cervelo S5 uses a similar design, just with a top bar in place.

Factor says the standard version of the handlebar is available in five sizes, equating to 110-150mm effective stem lengths, while sticking to 38cm-wide across all of those options (as narrow as the 2026 UCI regulations will allow). 

There is also a 'Hi-Rize' version of the handlebar, in 110, 120 and 130mm effective lengths.

The fastest UCI-legal road bike in the world

Factor isn’t shy about its claims around the One’s aerodynamic prowess, which it says have been proven in its own wind-tunnel tests and through third-party validation.

The most striking difference compared to a typical road bike is the wide-flaring fork legs, coupled with the deep effective head tube. The fork shoulders also feature a 'chin' protrusion to engage with the oncoming air sooner.

It’s worth noting that the One uses a bayonet fork layout, enabling the effective steering axis to remain in the typical place, while enabling the free-floating forward section to extend outwards.

Naturally, there’s the custom handlebar in the mix, which features a 'neutral' section to preserve handling. But, all together, the front-extending design is said to enable the One to control airflow more effectively before it passes over the rest of the bike, while making it more stable in crosswinds, beyond the typical 15-degree drop-off Factor says it observed of competitor bikes.

The wide-stance fork legs are also designed to break laminar airflow, enabling the rider’s moving legs to pass through the disrupted flow more easily. Meanwhile, air is said to pass more efficiently between the fork legs and wheel-tyre system. Factor says the design “eliminate[s] tyre spillover turbulence”.

Factor also says it has oriented the fork-mounted brake mount at a slanted angle to help reduce drag caused by the caliper.

Scores on the doors

Despite its ostentatious looks and progressive design, the Factor One ticks the major compatibility boxes.

It can sport up to 34mm-wide tyres (although Factor says it’s aerodynamically optimised for 28mm rubber mounted to a 23mm-wide internal rim) and around 165-170mm crank lengths.

A frame is said to weigh 900g in a size 54cm, with the fork adding another 540g – unsurprisingly heavy given its size. Gitelis confirms that the frameset uses a mix of Toray 30T, 40T and 46T Toray carbon, plus pitch and Nippon graphite fibre.

The frameset uses CeramicSpeed bearings throughout, including a Solid Lubrication Technology headset, and is matched to Black Inc Sixty Two wheels.