Factor Vis Vires Dura-Ace Di2 – first ride review

Production race bike with superbike credentials

Our rating 
4.5 out of 5 star rating 4.5
GBP £9,999.00 RRP

Our review

Radical design delivers exclusivity and an impressive, aggressive ride
Skip to view product specifications

The Vis Vires is the radical new race bike from British brand Factor, makers of the £25k Aston Martin One-77 superbike, itself a rebranding of the original Factor 001


Whereas those were ultra-exclusive superbikes – the 001 initially conceived as a showcase for Factor’s parent company, motorsport specialists bf1systems – the Vis Vires is a true production bike, albeit one that comes with an advanced power meter and a chassis like nothing else. BikeRadar were the first to have ridden it.

Ride & handling: Ultra stiff, with instant responses

The Vis Vires impressed instantly with its very high stiffness. The further and harder we rode it, the more impressed we were. Punching up short inclines with the power read-out into four figures, the chassis was unflinching. 

The bottom bracket, head tube, front and rear triangles, stem, bar… It’s massively rigid everywhere and there’s no weak link. We had no idea what to expect from this frame layout but we wouldn’t have put money on it being this stiff. Whether sprinting in a big gear or winching up a steep gradient and torturing the frame with torque, the Vis Vires remained ready for anything we dished out. 

Crucially, given the frame’s beef, the all-carbon Black Inc 50C wheels can keep pace. Flimsy hoops under this frame would be like Usain Bolt in stilettos, but the 50Cs are on a par with the likes of Zipp 404s for stiffness (which is to say that they’re very good and only eclipsed by Reynolds Aeros and carbon-spoked wonder wheels such as Lightweights). 

Factor vis vires :
Jonathan Ashelford/Future Publishing

It’s impossible to comment meaningfully on the aerodynamic speed of the wheels from one road ride, but they certainly proved stable in the blustery conditions we encountered.

Braking in the dry was strong, and there was loads of modulation at our fingertips. Factor must have done a lot of work to reinforce the areas around the mounting posts and refine the leverage ratios, because most TT bikes we’ve ridden using this type of aero V-brake exhibit far less impressive stopping characteristics. Wet braking will be a separate, tough test for the wheels, and the high track temperatures of a mountain descent harder still.

Shimano’s 11-speed Dura-Ace Di2 is quickly becoming familiar, so we’ll pause on it only to say that the front shifting is superb, even without matching Dura-Ace chainrings. The rear shifts are quick and accurate.

The Vis Vires handles like a thoroughbred racer thanks to aggressive geometry. Our size 56 test bike has a short 985mm wheelbase, stubby 403mm chainstays and a keen 73.25-degree head angle. 

It sounds as though it should steer faster than you can imagine, but the reality is slightly more settled than that. When we had the chance to push the Factor past 40mph it remained stable, carving lines around corners with the precision of a pair of compasses. 

Two characteristics take slightly more getting used to – the lockstops that save the Twin-Blade fork from hitting the frame but limit the steering angle at low speed, and the instant response that is the payoff for that fork design. 

You don’t realise the extent to which your inputs are blurred by flex, even on very good bikes, until you ride the Vis Vires. To start with, the sharpness of its reactions can surprise you – it’s like using a friend’s computer that has the mouse speed cranked up; it takes a moment to recalibrate your inputs. Once you’re tuned into it, though, the Vis Vires is a joy in the corners.

The original Factor 001 was criticised for its hard ride. While it was understandable in that bike, because it was built as a showcase for bf1systems’ skills, the team acknowledge that the Vis Vires had to be much better, and it is. This is a race machine, not a sportive bike, but it takes the edge off bumps and damps vibration effectively. We’d gladly do a century ride on it, and if you need more comfort you should be looking at a Trek Domane or similar.

But is the Vis Vires really aero? That’s always a hard question to answer based on riding alone, especially in windy conditions and on unknown roads. For all their expertise, Factor’s engineers aren’t aero specialists, and are clear that aerodynamics weren’t the primary goal of the bike. 

However, when a bike is this stiff and well resolved in all other areas, any aero gains are a bonus. This is how the Scott Foil was conceived, and that’s precisely why Factor used that bike as one of their benchmarks. They claim they match the Foil for stiffness and beat it for aerodynamics across the full range of wind angles. We hope to do some slightly more scientific testing once we get a bike for an extended period.

What we can say is that the Factor’s small side profile, compared to some other aero bikes, seems to render it impervious to crosswinds. Along with the very stable Black Inc 50C wheels, this is an aero road bike that even flyweight riders could take out on a blowy day without fear.

Frame & equipment: Radical shapes and high-tech kit

The Vis Vires is characterised by its Twin-Vane down tube and Twin-Blade fork. The team at Factor wanted to preserve these signature features from the 001 but without compromising the ride. 

The split down tube is made from two small airfoil tubes, braced against each other to provide lateral rigidity and meeting at the large and very complex bottom bracket. While not the original purpose, wind tunnel tested revealed the Twin-Vane down tube to be effective at handling the wash from the front wheel, prompting development to follow this direction. 

The vis vires has a split down tube, dubbed the twin-vane:
Jonathan Ashelford/Future Publishing

The Vis Vires has a split down tube, dubbed the Twin-Vane

The lower section of the seat tube is also split. The seatstays are very thin, to provide comfort, and they meet the seat tube well below the top tube to create a cantilever effect that encourages the seat tube to give slightly and do its share of bump damping.

The Twin-Blade fork is even more radical than the frame. The stem is an integral part of the structure; the point at which it meets the fork legs is effectively the top crown and responsible for the steering integrity, with a smaller, moulded lower crown providing the lower bearing interface beneath the head tube. 

Although this is, strictly speaking, an external steerer or hinge-type fork, there is a small compression rod inside the head tube to adjust the headset preload. It’s an extremely rigid design because the fork legs are fixed above and below the head tube. The TRP V-brakes are integrated into the rear of the fork legs.

The stem isn’t the prettiest but its functional contribution benefits the overall aesthetic: there’s an integrated Garmin mount, the headset mechanicals are hidden from view, the cabling is routed completely internally, and the rear of the stem is more aerodynamic than on a regular setup. 

Of course, it does mean that you can’t change the stem yourself should you wish to alter the position, so Factor have accounted for that. Three stem lengths are available (90mm, 100mm and 115mm), and 5mm-thick C-shape spacers allow further tweaks in every direction. Setting the reach should be easy for most riders, though the vertical adjustment might be insufficient for anyone looking for a more upright or completely slammed position.

There are two versions of the Vis Vires – the Dura-Ace Di2 we tested, and the Ultegra Di2, with complete groupsets equipped accordingly. Both roll on 45mm full carbon clinchers from new Asian brand Black Inc, who are still to launch in Europe. The hoops impressed Factor sufficiently for them to switch from the Easton models they had been planning to use. The tyres are top-quality Vittoria Open Corsa CX, co-branded for Factor.

The finishing kit is top notch and customised for Factor. The ENVE Composites Compact carbon handlebar has custom internal cable routing; the saddle is Fi’zi:k’s new range-topping, ultra-light Arione 00 with a colour-matched orange stripe. Even the very high-quality bar tape is colour-coded with orange contrast stitching.

The factor power crank :
Jonathan Ashelford/Future Publishing

Factor Power Crank 

The big spec highlight of the top model is the Factor Power Crank, an advanced crank-based power meter that’s entirely of their own design. It has a high sampling rate, left/right split, detailed efficiency analysis and sophisticated temperature compensation technology that’s meant to make it all but immune to drift. It’s rechargeable, so you never need change the battery, and the only calibration it should need is carried out at the factory before delivery. 


This bike also comes with a Garmin 810 bike computer (and heart rate strap) and Scicon AeroComfort bike travel bag. You could actually argue that it’s good value at this price.

Product Specifications


Name Vis Vires Dura-Ace Di2 (13)
Brand Factor

Available Sizes 51 54 56 58 61
Cassette Shimano Dura-Ace Di2 9070, 11-speed
Cranks Factor Power Crank
Fork Factor Vis Vires Twin-Blade
Frame Material Factor Vis Vires, UD carbon with Twin-Vane down tube
Front Derailleur Dura-Ace Di2
Front Tyre Vittoria
Handlebar ENVE Compact, UD carbon
Rear Derailleur Dura-Ace Di2
Rear Tyre Vittoria
Saddle Arione 00
Seatpost Factor
Shifters Dura-Ace Di2
Stem Factor
Weight (kg) 6.9
Weight (lb) 15.2