Calling a bike fast without independent data to back it up is journalistically suspect.
But you don’t need data to tell you when a bike feels fast, and when its riding manners favour aggressive riding. Bikes may be inanimate objects without agency, but some give the distinct impression they want to be ridden quickly, whether that’s by virtue of riding position, styling or the sensation of pedalling.
The second-generation Factor Ostro VAM is one of these bikes, and it does it with a combination of all three. It looks fast standing still, and it feels very fast when you’re standing on the pedals, or in an aero tuck with your hands draped over the bars.
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Factor Ostro VAM design and development
According to Factor founder Rob Gitelis, the overriding design aim for the second generation of the Ostro was not to ruin an already excellent bike. Going faster via aero gains was the main focus, but this couldn’t be allowed to upset the existing balance of stiffness, handling and weight that made the original Ostro such a good bike, one Cyclist tester Jamie Wilkins described as ‘the best he’d ever ridden’ back in 2022.
At first glance, the updated Ostro’s overall shape hasn’t changed dramatically, but closer inspection reveals a more organic, flowing design where the boxiness of the tubes has softened and the whole bike appears slimmer, because it is. Factor says the new Ostro saves seven watts at 48kmh compared to its already slippery predecessor and, while frame weight has barely changed, complete bikes shed around 270g in total thanks to a new wheelset.
We’re accustomed to aero road bikes using truncated aerofoil (or ‘kamm-tail’) tube profiles throughout and the Ostro is no exception, however it’s interesting to observe how aero profiles are now evolving, with tube cross-sections elongating and narrowing to reduce frontal area after years of comparatively boxy D-profile designs.
The UCI dropped its strict 3:1 length:width ratio limit for frame tube cross-sections back in 2017 (the rule change was extended to components such as seatposts and bars for 2023), a regulation that was in part responsible for the popularity of truncated aerofoils. However the updated rules didn’t bring about the dramatic change one might have expected, and we certainly haven’t seen a return to the full aerofoils of first-generation aero bikes such as the original Cervélo Soloist – which had a true teardrop down tube – because these don’t offer the best overall trade-off in aero, weight, stiffness and strength.
According to Factor head of engineering Graham Shrive, the ratio rule wasn’t necessarily the biggest limiting factor, as the profiles that worked best for aerodynamics were pretty close to 3:1 anyway. More important was the rule on minimum tube width, which changed relatively recently from 25mm to a tiny 10mm.
‘Functionally going below 25mm causes lots of problems with things like cable routing, stiffness, bottle mounting, and just general strength, so it’s always a bit of a juggle,’ says Shrive. But the Ostro is one bike that takes advantage of this change, with a top tube that tapers dramatically towards the rear, all but disappearing in side-profile as it reduces down to around 15mm in height. In plan view it’s close to a teardrop thanks to the addition of a Tarmac SL8-style nose cone.
Streamlining is the theme throughout. The previously slab-sided head tube has put on a corset and acquired a pronounced hourglass figure, while the fork has lost some bulk and melds more naturally with its brake calliper and thru-axle.
Where the seat tube nears the rear wheel, its cross-section becomes concave at the rear as if to wrap around the tyre. The frameset and wheels are optimised for 28mm tyres, and taking a horizontal slice out of the bike in this area would reveal another near-perfect aerofoil made up of seat tube, tyre and rim.
Other changes are more prosaic, but notable. The seat clamp now uses a clamping plate at the rear of the seatpost rather than a wedge in front of it, a welcome change as wedges invariably stick and can make minor saddle height adjustments needlessly frustrating. This system does use two tiny grub screws however, so care will need to be taken in the long term to avoid damaging them. Oh and don’t undo one too far and drop it by the roadside, you’ll never see it again.
Factor Ostro VAM build
Factor doesn’t do budget builds and our test bike is dressed to kill with full Dura-Ace and the brand’s new Black Inc 48/58 wheelset, which is claimed to weigh just 1,290g and features carbon spokes along with new high-flange hubs designed to increase lateral stiffness.
The Ostro is the consummate modern all-round race bike. Whether you can feel specific aero gains or not, the blend of stiffness, pin-sharp handling and refinement the Ostro offers is intoxicating. As a complete riding experience it’s up there with the very best, with the usual race bike caveat that it’s best enjoyed at speed and on better surfaces, as ride quality is relatively uncompromising, although certainly not harsh.
It’s difficult to pick apart the Ostro’s ride without lapsing into cliches because it’s simply very good. It’s a satisfying thing to try very hard on, one that rewards your best efforts with both the sense of speed and actual speed and inspires confidence when you point it downhill and carve through a series of bends.
It doesn’t hurt that it’s respectably light too, Factor does of course offer a dedicated lightweight bike for climbers in the shape of the O2 VAM, but the Ostro is a very willing partner uphill and doubtless faster across varying terrain in the real world.
The balance between on-paper speed and real-world usability feels well-judged with spec choices like the mixed depth 48/58 wheelset, which doesn’t catch excessive amounts of wind and features 23mm-internal width rims that are ideal for 28mm tyres.
Factor Ostro VAM review verdict
I’m going to get into trouble for slipping into car analogies again but here we go: if the Colnagos and Pinarellos of this world are Ferrari and Lamborghini, Factor is EV wunderkind Rimac. Factor’s history is shorter than some of its rivals – because you can’t cheat the passage of time – but it offers something genuinely substantive.
The brand can’t point to its victories in the 1960s nor dangle a totemic lugged steel racer in its foyer as a reminder of its roots, but it can draw a straight line from some hard science to a very fast bicycle, and highlight its bikes’ impressive palmares in modern-day racing.
The biggest problem for any new race bike entering the arena is that most new bikes are excellent, outstanding, game-changing and any number of other now-debased superlatives.
If a bike costing almost eleven thousand pounds is anything but excellent then it’s a problem, and we’re used to the idea now that the flagship designs are stunningly good, while the second and third tiers are merely bloody excellent.
Factor isn’t in the business of being all things to all riders, and so there isn’t really a budget version here. The Ostro is expensive and if you want one, you can’t save money with the ersatz version. Saying that, it’s actually significantly cheaper than flagship rivals such as the top spec versions of the Specialized Tarmac SL8, Trek Madone SLR and Cervélo S5.
If you need a reason to choose Factor over these rivals, it might be that obsessive attention to aero detail and hard-nosed engineering that sells it, or it might be that you like riding very quickly and you need your bike onside.
Factor Ostro VAM: specs
- Price: £10,799
- Weight: 7.1kg (54)
- Groupset: Shimano Dura-Ace
- Wheels: Black Inc 48/58
- Tyres: Vittoria Corsa N.EXT 28mm tyres
- Bar/stem: Black Inc Integrated Aero
- Seatpost: Ostro carbon
- Saddle: Selle Italia SLR
- Contact: factorbikes.com
