Felt F1x Di2 (2017)

Pure 'cross bike a pricey performer

Pros

- Ingenious 1x drivetrain shifting setup
- Sweet wheelset
- Fast, light, and stable

Cons

- Cassette too narrow for hilly courses
- Bar one size too big
- Saddle adjustment a bit tetchy

Review

How do you build a race-ready CX bike? You take a fantastic carbon frame and hang the most innovative high-quality components you can find on it; that’s precisely what Felt has done with the new cyclocross rocket, the F1x Di2.

There is a groundswell of support, and a corresponding number of new models, for the “all-road” bike – a machine that can take you anywhere and is equally at home on the gravel, in a Gran Fondo or on a bikepacking trip. This is not one of those bikes. It is a pure race machine, designed to go as fast as possible over difficult terrain and while being carried over obstacles. The super-rigid oversized frame tubes and stiff front fork mean that while it may not be the most comfortable CX bike on the market, it rockets forward like a road bike when power is applied and the rear triangle and fork keep their integrity no matter how much force is applied.

It’s light, too: just 7.44kg (16.40lb) for a 53cm bike without pedals, and a claimed frame weight of just 950g.

The design team at Felt were insistent on having a 1x electronic shifting system on this model, but since Shimano doesn’t offer a left-hand lever without shifter internals, they went ahead and reprogrammed the controls. They came up with a system where you tap either right-hand button for an upshift and either left-hand one for a downshift, effectively creating a sequential transmission perfectly suited for the rigors of ’cross, including some very neat internal cabling. The system sounds clumsy but it works brilliantly – just slap the side of the lever and you get the desired shift, even when wearing heavy winter gloves.

However, they undid some of their good work by offering a rather narrow 11-28 Shimano Dura-Ace rear cassette as standard to pair up with the 38-tooth Rotor Q CX1 wide/narrow single front chainring; not the end of the world, but plenty of riders in hilly areas will be swapping them out for something more forgiving.

Rotational weight is kept to a minimum thanks to custom shallow-profile carbon tubeless DT Swiss wheels and matching Schwalbe X-One tubeless tires. This wheel and tire combination teams up nicely with the Shimano’s hydraulic disc brakes that provide the usual superb stopping power and bite plus excellent control in all weather conditions. They also feature pads that self-adjust for wear for more consistent lever feel, and the thru-axle hub interfaces at both ends keep the rotors from rubbing even under hard cornering.

Any seasoned ‘cross racer will tell you that mud on your frame is the enemy: to combat this, Felt removed the seat-stay bridge, increasing tire clearance but still maintaining lateral stiffness thanks to a wider BB386 bottom bracket.

The UHC Advanced + TeXtreme carbon fiber frame is incredibly light and strong, and the shoulder-friendly top tube and replaceable rear derailleur hanger are nice touches that CX racers will appreciate. The Prologo X Zero TiRox saddle is robust yet comfortable, but the elastomeric insert in the 3T seatpost with its spline-type adjustment makes it tricky to get the saddle angle just right. The 3T Ergoterra Team Stealth handlebars, coupled with a 3T ARX II Team Stealth stem, are nice to hold and have a pleasant ergonomic shape – but they are very wide relative to the frame size. If you like wide bars that’s fine, but otherwise it’s probably worth asking your bike shop to let you trade down one bar size.

Overall this bike is frighteningly fast, brilliantly accessorized and remarkably stable. Swap the rear cassette for something more manageable, take some time to get the saddle position perfect and consider the bar size – then you have the perfect CX race bike.