The Factor O2 VAM, one of the lightest bikes of recent years, promises to combine minimal weight and a touch of aerodynamics like no other. It checks all the boxes with details like the integrated seat post. But can the bike live up to expectations, and does the road scene still need climbing specialists?

Factor O2 VAM | 6.93 kg in size 56 | € 9,499 | Manufacturer’s website

Factor Bikes and racing go hand in hand. The brand has an undeniable need for speed, and every model in their portfolio is designed to go fast. Factor’s approach was evident in our gravel race bike group test where the Factor OSTRO Gravel proved to be an uncompromising aero gravel bike. Likewise, the new O2 VAM is all about creating the fastest bike on the market. However, true to O2 heritage – aerodynamic efficiency – isn’t its selling point. The bike is all about excelling on the climbs. What has changed on the latest VAM is the introduction of aero-optimisation on a climbing bike. Factor refer to this as “maximum aerodynamics at minimum weight”, clearly making weight savings the top priority. To this end, the speed experts have reached deep into their bag of tricks, but has it paid off?

Light as a feather and fast as lightning? – Factor O2 VAM

The singular goal of creating the perfect climbing bike still demands maximum weight savings, even in times of aero-everything. That’s because riding uphill still mainly consists of fighting gravity. And you’ll typically ride slower when climbing, at which point aerodynamics become a lot less relevant. But depending on the brand, climbing bikes can take very different approaches.
Factor have identified two categories of climbing bikes: the pure, lightweight climbing specialists that completely ignore aerodynamics, and the all-rounders. The all-rounders promise to strike a good compromise between weight and aerodynamics, resulting in a consistently well-performing bike for every scenario, though with a higher weight.
And this is exactly where Factor step in to introduce a third category, offering maximum weight savings with a touch of aero-optimisation, so to speak. The goal was clear, and the boss’ instructions were unambiguous: “Make me the most aerodynamic sub 700 g frame possible”, which can only mean creating a bike while taking an approach that we’ve never seen before. According to Factor, this also means that the complete “race-ready” bike, i.e. including the pedals and transponder, tips the scales at the UCI weight limit of just 6.8 kg. However, that wasn’t entirely the case with our size 56 test bike. Equipped with the SRAM Force AXS eTap groupset, which we admit isn’t top end, the bike weighs 6.93 kg without pedals. However, it should shine with the same stiffness as the aero optimised Factor OSTRO VAM.

Factor have made the pursuit of innovation their motto, shouting it out to the world with the O2 VAM.

Weight savings and wind tunnels? – The Factor O2 VAM

Saving weight sounds simple at first: Just use as little material as possible. But, as always, the devil is in the details, and the 6.8 kg mark isn’t easy to reach, even with modern technologies and materials.
The Factor O2 VAM certainly looks lighter than most other bikes on the market with its heavily tapered top tube, aerodynamic-ish down tube, and dainty seat stays. You’ve also got the fork, of course, on which they clearly used as little material possible, though the aerodynamics weren’t entirely neglected either. The smooth transition between the fork crown and the frame is particularly reminiscent of the aerodynamic OSTRO VAM and OSTRO Gravel.

Is this where they’ve hidden the aero gains? Factor promise to save a few watts with the specially shaped and beautifully integrated fork.

This is complemented by one of the main features of the O2 VAM – the integrated seat post isn’t just for looks, but also allows Factor to save vital grams and watts. It’s a cool solution that lets the bike stand out from the crowd.
But whether all the aero claims can be backed by hard facts can only be proven in the wind tunnel. And yes, the O2 VAM was taken there! As perhaps the only climbing bike and with completely different requirements compared to thoroughbred race bikes, Factor also had to break new ground here. Air flow behaves very differently at 20 km/h compared to 45 km/h, and so the seat tube in particular has been made significantly wider to hide the rear wheel in the slipstream.

The skinny head tube doesn’t just save valuable grams but also serves some aero purposes.
Factor go to the extremes of attention to detail with the integrated seat post.

The high-end components of the Factor O2 VAM

Factor went all in when speccing the O2 VAM. Thanks to their cooperation with Black Inc, the bike was supplied with top notch components. And so the O2 VAM comes equipped with the Black Inc Integrated Barstem known from the OSTRO VAM – ergonomic, aero-optimised, and lightweight, of course. As the icing on the cake, the wheels have been specially developed for the O2 VAM. Thus, the Black Inc 28//33 are at the cutting edge of wheel technology, designed for 28 mm tires with an external rim width of 28.5 mm and a wide 23 mm internally, yet tipping the scales at just 1,118 g!

Polished to a high gloss: You’ll hardly find a fancier and higher quality one-piece cockpit than that from Black Inc.

Matching the wheels, Factor spec Goodyear Eagle F1R tires. The € 9,499 model on test is finished off with a SRAM Force eTap AXS groupset. Unfortunately, our bike didn’t yet feature the latest iteration. Factor don’t bother with a power meter either. It’s available as an optional upgrade for just under € 300. The CeramicSpeed bottom bracket is a rarity for a stock bike, which once again demonstrates Factor’s consistent pursuit of efficiency and race performance.

Tuning-Tipp: A power meter to claim that K/QOM.

Maximum efficiency and ceramics go hand in hand. With the CeramicSpeed bottom bracket, Factor maximise pedalling efficiency.
However, the old SRAM Force eTap AXS drivetrain doesn’t quite do the high-end bike justice and adds unnecessary weight.

Factor O2 VAM 2023

€ 9,499


Seatpost Factor D-Shaped
Brakes SRAM Force AXS 160/160 mm
Drivetrain SRAM Force eTap AXS 2x12
Stem Black Inc Integrated Barstem 110 mm
Handlebar Black Inc Integrated Barstem 420 mm
Wheelset Black Inc 28/33 12 x 100/12 x 148 mm Through Axle
Tires Goodyear Eagle F1R 700 x 28c 28
Cranks Sram Force AXS 170 mm
Cassette SRAM CS-XG-1270 10-33T

Technical Data

Size 45 49 52 54 56 58 61
Weight 6.93 kg

Specific Features

integrated seatpost
CeramicSpeed bottom bracket

Like the British brand’s other bikes, the O2 VAM is in the high-end segment in terms of pricing. The “Premium Package” includes a frame set and cockpit, and is available for € 6,049. If you want to add the Black Inc 28//33 wheels, you’ll have to fork out € 8,599. The price for a complete bike with either a SRAM Force eTap AXS or Shimano ULTEGRA Di2 groupset is surprisingly low, setting you back by € 900 more. But for a SRAM RED or Shimano Dura-Ace Di2 groupset, the total price is a whopping € 11,999. The option of a custom paint job is particularly noteworthy, giving your creativity free rein for a surcharge of just under € 500.

The geometry of the Factor O2 VAM

Factor have redesigned the new O2 VAM from the ground up, and they haven’t stopped at the geometry. While based on the predecessor, there’s a lot that Factor have learned. To ensure the slightly upright riding position preferred when climbing, the O2 VAM has a little more stack and less reach. This is achieved via a shorter top tube and steeper seat tube angle. To perform on steep terrain, the O2 VAM places the rider a little more over the bottom bracket, and into a more upright position for long climbs.

Size 45 49 52 54 56 58 61
Seat Tube 560 mm 580 mm 620 mm 650 mm 680 mm 700 mm 720 mm
Head Tube 109 mm 117 mm 134 mm 154 mm 172 mm 196 mm 211 mm
Head angle 71.1° 71.7° 72.5° 72.5° 73.3° 73.3° 73.3°
Seat angle 75.5° 74.5° 74° 74° 73,5° 73,5° 73,5°
Chainstay 405 mm 405 mm 405 mm 405 mm 405 mm 408 mm 410 mm
Wheelbase 970 mm 969 mm 971 mm 985 mm 987 mm 1,006 mm 1,022 mm
Reach 360 mm 367 mm 373 mm 381 mm 389 mm 401 mm 410 mm
Stack 502 mm 514 mm 535 mm 552 mm 574 mm 597 mm 611 mm

The sky’s the limit – Riding the Factor O2 VAM

A bike with such clear goals raises high expectations, and the Factor O2 VAM can certainly deliver. As a super direct bike, it’s very precise and manoeuvrable, accelerates incredibly easily, and is just a blast on the climbs. Steep gradients and winding climbs, in particular, really put a smile on your face with this bike, revealing the true strengths of its low weight and responsiveness – a dream on steep inclines and long Alpine passes.
If you venture away from the climbs, the O2 VAM will quickly feel outside of its comfort zone, because the direct handling, which is so appreciated when climbing, feels nervous and robs you of confidence on the descents and straights. Experienced riders will know how to deal with this, but beginners should better take it slow first. As such, the bike is no match for all-rounders or aero bikes despite the aero-optimisation, and the increased drag is clearly noticeable, especially on flat terrain. But the moment you approach a hill and the O2 VAM lets you climb effortlessly to the top, you’ll forget all that and find yourself grinning once again.

Who is the Factor O2 VAM for?

Weight fanatic, climbing fan, and flush with cash – ring a bell? In that case the Factor O2 VAM might be perfect for you. Those who live and ride in mountainous terrain and prefer climbing rather than blasting down descents will love this bike. That said, you must keep in mind that all that climbing prowess comes at a cost, unable to hide the lack of aerodynamics and nervous handling on the descents. But if that’s a compromise you’re willing to accept, you’ll get a truly unique bike that’s sure to put a smile on your face.

Conclusion on the new Factor O2 VAM

Absolute climbing performance. That’s what the Factor O2 VAM promises – and that’s what it delivers! Purpose built down to the finest detail, it performs convincingly with its super-agile handling and mountain-goat-like capabilities. Technical refinements like the integrated seat post and low-speed aerodynamics are the cherry on top. It’s an excellent and unique option for climbers, and not just because of the prominent Factor logo on the down tube. The high-end CeramicSpeed and Black Inc components also make the bike stand out from the crowd.


  • the ultimate climbing bike
  • dynamic handling and extremely fun on the climbs
  • beautifully integrated seat post
  • customisable paint job


  • can’t keep up with all-rounders on the flats

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Words: Calvin Zajac Photos: Jan Richter, Mike Hunger