Factor Ostro VAM review

The Factor Ostro VAM does an excellent job of blending the drag-reducing traits of full blown aero bikes such the Factor One with the light weight of dedicated climber’s bikes, such as the Factor O2 VAM.
Consequently, it look set to join the new Giant Propel Advanced SL 0 as one of the best all-round race bikes on the market today.
Factor has created a frame that includes sleek, truncated aerofoil tube profiles and novel aero features at a competitive claimed weight of 780g.

Cyclist tested the top-tier Ostro VAM build, which was specced with a SRAM Red eTap AXS groupset and Black Inc Fourty Five wheels. It weighs just 7.2kg for a size 56 and costs £9,450.
The Ostro combines the best of all worlds out on the road. It feels stiff, responsive and light, yet offer decent comfort and feels like it holds high speed easily too. Factor has done an exceptional job at balancing opposing ride attributes.

Factor Ostro VAM development

The aero all-rounder category has become the vanguard of most brands’ ranges and the default choice of most pro teams. After all, drag even affects how fast you climb a mountain.
But so does weight, and aero bikes tend to be heavier because they have more complex tube shapes. Reconciling lightness and aerodynamics is the big challenge, then, which is where the Factor Ostro VAM comes in.

‘In any new project, we use a ranking system for aero, lightness and comfort,’ says Factor’s owner, Rob Gitelis. ‘The Ostro had a very clear goal – to be the most aero 780g frame. We set the weight budget, then chased aero. Then it had to move forward in other areas, such as fully internal cabling.’

Factor Ostro VAM frameset

The Ostro’s frame profiles are derived from NACA airfoil shapes, with aggressive truncation that Factor says was only possible because it owns its factory and was therefore willing and able to invest in materials and methods, despite the production difficulties and costs.
One such example is the ‘Reversing Flow Energising Channel’ under the fork crown. This is based on the theory that the top of a rotating wheel moves at twice the speed of the bike itself, dragging air forwards into air that’s trying to flow the other way around the down tube.
Factor says the channel under the fork crown accelerates this air through the fork, thereby blasting out the stagnant air that might otherwise stall behind it. So given this, was Factor able to achieve its design brief?
‘The 780g target was very ambitious but we reached it,’ says Gitelis. ‘And in all testing – ours and that of the Israel-Premier Tech team – the Ostro is the fastest bike in the WorldTour.’

Factor Ostro VAM build

This test bike came built with a SRAM Red eTap AXS groupset with 48/35, 10-33t gearing and sister brand Black Inc’s aero Barstem and Forty Five wheels, the latter developed specifically to suit the Ostro. It also benefits from the optional upgrade to a CeramicSpeed OSPW – oversized pulley wheel system.
The Forty Five wheels seem to fly like they are 80mm deep yet shrug off gusts as if they’re 30mm, a neat trick indeed. They’re laterally stiff too, backing up the frame’s power transfer under sprint efforts.

Factor Ostro VAM geometry and sizing

The geometry is the same unapologetically race-focussed setup as Factor’s O2 VAM dedicated climber’s bike, which makes it easy for the pros to swap between bikes.
Six sizes are available, their numbers reflective of frame stack height rather than top tube length, so check the geometry table carefully, or better yet get a bike fit with Factor’s UK distributor Vires Velo.

Riding the Factor Ostro VAM

Overall stiffness is immense, yet at the same time the Ostro is uncannily comfortable, an incredibly useful attribute on long rides where filtering out vibrations really helps reduce fatigue. And I say this with 25mm tyres fitted – there is clearance enough here for 32s.
Climbing is similarly superb. I live in the Pyrenees so have plenty of opportunity to test this, and the Ostro is undoubtedly faster than a slightly lighter climber’s bike over long, mountainous routes. 

Factor doesn’t make much noise about the bike’s handling, but it should. It’s phenomenal. No bike has ever given me as much confidence on descents; I took a full minute off my best time down the west side of the Col du Tourmalet and I’ve gone ‘full send’ on plenty of occasions. The balance of agility and high-speed stability is exquisite.
SRAM’s Red eTap AXS group has been around for a while and the braking is fantastic.
The shift logic is ingenious too, so it’s a shame that the shifts themselves are relatively ponderous and that the benefit of the 12th sprocket gets absorbed by the oddly small 13-tooth difference between the chainrings. SRAM claims that gap improves front shifting, but my jury’s out.
The CeramicSpeed OSPW might appear like lavish jewellery but I genuinely feel it makes a difference when I pedal, and if you find that hard to believe then you only have to flick the cranks backwards at a standstill – I’ve never seen a drivetrain spin like it.

Factor Ostro VAM verdict

I’ve ridden the Ostro a lot – 3,000km and 70,000m of climbing – I’ve pushed it as hard as I can and taken it on myriad all-day rides, and my admiration for it only increases. I get the question a lot, ‘What’s the best bike you’ve ridden?’ This is my new answer.

Factor Ostro VAM spec

Pick of the Kit

SunGod Vulcans sunglasses

There’s a lot to like about the Vulcans, but foremost is that I never have to push them back up my nose. They’re extremely secure and this is achieved through fit rather than force – you barely feel them.
The big lens is both trendy and well suited to fast, head-down riding as the frame is kept well out of your vision, and its tint provides excellent clarity on sunny days. They don’t steam up easily, either.
Best of all is the zero-cost custom programme, which lets you tailor and coordinate every aspect, including the ear socks and side logos.

• Buy the SunGod Vulcans sunglasses from sungod.co

Factor Ostro VAM alternatives

Factor O2 VAM

The Ostro is likely faster over a given course, but with its entire frameset claiming to come in under a kilo the O2 VAM (£9,450) is the one to pick if climbing is your thing.

Factor One

The versatile Ostro VAM might marginalise Factor’s aero racer, the One (£9,300), but features such as the Twin Vane Evo split down tube promise considerable lateral stiffness to ensure the One still has a place.
Photos: Alex Duffill
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