Review: Factor O2 VAM


As Factor’s first platform (not counting the bonkers Vis Vires model that CEO Rob Gitelis inherited when he bought the company from bf1systems), it feels right that the latest generation of the Factor O2 VAM sits at the pinnacle of the range.

The brand’s line-up may have diversified down the years, but Gitelis has made sure the O2 hasn’t lagged behind in performance terms, for it has been revised every other year since its inception in 2017.

This revision feels particularly significant. It uses composite fabrication techniques from the Ostro VAM aero bike to match its bulkier counterpart in stiffness terms.

It uses sharply truncated tube profiles derived from the Ostro Gravel that engineering director Graham Shrive says ‘manipulate the formation of the “laminar separation bubble” and reattachment of the airflow’. (As far as my understanding goes, that makes the bike zoomy in wind.)

It preserves the bike’s signature light weight and also exploits the latest UCI rules around tube architecture, squashing the back end of the top tube down to just 10mm in height to build in some comfort.

Overall, it feels like Factor has woven threads of technology together from disparate projects to create what could be perceived as the perfect modern race bike.

By way of justification, Factor says it built a new production facility entirely for this bike, and it arrives with some staggering claims.

Versus the old O2 VAM, this one is said to be 12 watts more efficient at 48kmh, 35% stiffer, and sits near enough to the UCI weight limit ready to ride.

Tight and light

Bottom bracket stiffness wasn’t the only thing the O2 took from the Ostro VAM, as it also has the same handling geometry.

A steep head tube angle of 73.3° and tight 405mm chainstays help create a short 987mm wheelbase, which combined with trail of 58.6mm makes the bike as agile through turns as its low weight makes it uphill.

In terms of fit geometry, the O2 VAM has an extra 10mm of stack per size compared to the Ostro VAM. ‘We got feedback that many riders used the old bike with spacers as they prefer a more upright climbing position,’ says Shrive.

‘The O2 is made for going uphill so we added some height at the front.’

While my test routes aren’t blessed with the mountains this bike was designed for, the innumerable short, sharp climbs meant I could still rack up a lot of elevation in a relatively short distance, and the O2 VAM’s climbing prowess made itself abundantly clear very quickly.

I’ve never ridden a bike that felt faster uphill. Its 6.5kg weight is obviously key, but there are aspects of the way the bike can ascend – sometimes floating, sometimes zipping – that can only have been achieved by blending more than just light weight into the design.

Features such as the wide bottom bracket junction and the carbon spokes of Factor’s component brand Black Inc’s 28/33 wheels impart a responsiveness to effort that perfectly complements the frame’s waif-like stature.

The narrow, clean front end that helps aero efficiency is achieved by running cables internally, with CeramicSpeed’s hard-wearing SLT headset bearings specced to reduce maintenance

The truncated aerofoil tube profiles may also help on shallower ascents because the bike certainly didn’t feel draggy at higher speeds on the flat.

Its geometry plays its part too, combining with the light weight to create a bike that is thrilling to whip through sharp turns.

All up, no down

Something I find as impressive as the bike’s ride attributes is that Factor has achieved such a design without much compromise.

Despite the use of ultra-high modulus fibres (essential to create the extreme stiffness-to-weight ratio) the bike isn’t harsh to ride, thanks to the controlled deflection at the saddle afforded in part by the flattened top tube.

An integrated seatpost does introduce adjustability issues, yet the topper allows for so much adjustment that the seatpost may not even have to be cut in some cases.

While I do think the bike’s performance as a whole owes a lot to Black Inc’s freakishly light (claimed weight 1,146g) wheels, throughout the O2 VAM’s design it seems that Factor has figured out how to achieve peak performance without many of the drawbacks that are usually associated.

The result speaks for itself as soon as the road tilts upwards. My main question is where this leaves the Ostro VAM.

Factor’s bikes are too expensive for the majority of riders to own more than one, and the O2 VAM is now nearly as quick but a whole chunk lighter.

I know which one I’d invest in given the choice, but perhaps that’s the point.

Factor is giving customers the ability to choose, knowing that whichever direction they go, they’re unlikely to be disappointed.

The Spec

Model Factor O2 VAM
Price $18,790
Weight 6.5kg (56cm)
Groupset Sram Red AXS
Wheels Black Inc 28/33
Finishing kit Black Inc Integrated bar/stem, Selle Italia SLR Boost saddle, Goodyear Eagle F1 R 28mm tyres



  1. Black Inc’s 28/33 wheels are astoundingly light at a claimed 1,146g. Features such as carbon spokes make them responsive to complement the frame’s light weight
  2. The squashed seat tube permits flex at the saddle, improving comfort
  3. The head tube presents a narrow frontal area thanks to a D-shaped fork steerer accommodating the internal hoses

Cyclist Australia/NZ