Mud splatters as aero modelling in Alex Dowsett’s video discussion of his new Factor team bike

Grimy Essex road-spray taking the place of more advanced technologies is a new one on us

Alex Dowsett, rider for Israel Start-Up Nation, has posted a video to his YouTube channel discussing his new Factor team bike, with particular praise for the tubeless setup and aero profiles.

Teammate Chris Froome sparked controversy last week in a similar style video, with frank criticism of his Factor’s disc brakes and “flexible” handlebars.

Alex Dowsett’s team bike

For 2021, Dowsett is riding the Factor Ostro VAM, which is part of that new crop of bikes creating an elision between aero and climbing, being a single frameset to do it all.

Last year, Dowsett would generally use the Factor O2 VAM climbing bike as his training bike while racing on the Factor One aero bike – upon which he won stage eight of the 2020 Giro d’Italia.

“I feel like I won that stage because of the qualities of that bike, but on that climb I almost lost the stage. [The Ostro VAM’s] extra half kilo or a kilo lighter could have helped me,” Dowsett said.

Although weighing in at 7.75kg with 60mm deep wheels, Dowsett’s new Factor Ostro VAM is still pretty far off the UCI weight limit of 6.8kg.

To be fair, Dowsett did seem a little surprised by the weight. There’s a number of factors that could affect accuracy – even the temperature of the garage he filmed and weighed the bike – although this would only likely account for a hundred or so grams.

Aero profiles

Alex Dowsett Factor Ostro VAM

Credit: Alex Dowsett / YouTube

“Now, the shapes of the frame are something that I found super interesting,” Dowsett said, paying particular attention to the fork and downtube design.

The Factor Ostro – as we’re seemingly increasingly often in aerodynamic designs – has very widely spaced fork legs in order to improve the airflow around the wheels.

“I’ve noticed you can see the pattern from the wheels of the mud, which is representative of how the air coming off the wheel has changed compared to any other bike I’ve ever had,” Dowsett said.

Alex Dowsett Factor Ostro VAM

Credit: Alex Dowsett / YouTube

Speaking more broadly about the tube profiles, Dowsett continued, “Factor, like a lot of other companies, uses a kammtail design because there is a UCI limit on the length of a tube and […] also a UCI limit on the width of the tube compared to the length.

“The way a kammtail works is it essentially starts off the tear drop shape and cuts off the end. Whilst not as efficient as the full tear drop shape, it still works better than having a full tear drop shape that [fits within the UCI limits.]

“It’s already noticeably quicker than anything I’ve ever ridden before. Immediately when you jump on the bike you’re quite blown away by the responsiveness and also the rigidity.”

Now, we won’t hold our breath for engineers to start using this method over wind tunnel testing and Computational Fluid Dynamics (CFD) analysis – but it was certainly an interesting take.

Wheels and tyres

Alex Dowsett Factor Ostro VAM

Credit: Alex Dowsett / YouTube

Black Inc, Factor’s in house wheel and finishing kit brand, supplies the hoops, with Dowsett currently plumping for the 60mm option. This year his options have been bolstered by the inclusion of a 45mm set, splitting the difference between last year’s deep and the shallow options.

Rubber-wise, Maxxis Padrone-TR tyres are being run in a quite modern 28mm width and tubeless setup – 25mm tubular tyres are still commonly used by many pro teams.

“One of their biggest qualities in my mind are their ability to not puncture – touch wood – I think I punctured once in a race last year and that was in Tirreno-Adriatico.

“We had one puncture in the Giro for the whole team, we didn’t have a single puncture in Strade Bianche for the whole team, so I guess that proves they’re pretty good.”

Drivetrain and brakes

Alex Dowsett Factor Ostro VAM

Credit: Alex Dowsett / YouTube

Dowsett didn’t dwell on his stoppers, rattling through the setup: “Dura-Ace brake calipers, Swissstop brake pads, Swissstop disc brake rotors, and it’s 160mm on the front and 140mm on the back.

“On the time trail bike, it’ll probably be 140 on the front.”

Interestingly, Dowestt confirmed that Dura-Ace was a choice, over a sponsor obligation: “At ISN we’re lucky not to be sponsored by a grouspet, the team just purchases Dura-Ace” – which is a ringing endorsement if ever there was one.

And nothing more is said on the matter. From the video it does look as though Dowsett is currently running a 140mm rotor on the front, however.

Dura Ace crankset

Credit: Alex Dowsett / YouTube

The drivetrain is a mainly Dura-Ace affair, but with a 4iiii dual sided power meter mated to the cranks and the bottom bracket bearings swapped out for CeramicSpeed alternatives.

“This is a training bike, so I haven’t got it, but normally I’d have the oversized ceramic speed pulley wheels.”