Serial innovators Cannondale have lifted the lid on an overhauled cross-country mountain bike, the F-Si. Designed in collaboration with some of the world’s best cross-country mountain bikers, the new F-Si hosts a number of modern mountain biking tech and features.
With an all-new Lefty fork out front, a revised geometry and a frame that’s claimed to be lighter than its featherweight predecessor, read on for nine things to know about the 2019 Cannondale F-Si cross country mountain bike.
1. A Game Changer from its Inception
Originally released back in 2015, the F-Si shook up the cross country mountain biking world with its scarily lightweight frame, single-sided front fork and limit pushing capabilities. With the all-new F-Si Cannondale claiming to have taken all that was good about its predecessor and improved upon it to create what the American brand calls its “ultimate racing hardtail”.
2. Lighter Than Ever
Tipping the scales at a feathery 900 grams, the F-Si Hi-MOD frame is claimed to be 80 grams lighter than its predecessor, with this saving increasing over 300 grams when factoring in the all-new Lefty Ocho front fork. Simply put, it’s the lightest mountain bike frame Cannondale has ever made.
3. And Stiffer Too…
Cannondale say the F-Si is stiffer than the outgoing model too. Rigidity and compliance both increase for reduced fatigue and better control. This stiffness is thanks to the F-Si’s proprietary BallisTec carbon construction which Cannondale claim, allows them tune the rigidity of the frame for stiffness where you need it and flex where you don't.
4. Revised Geometry
New bike, even better feel. Cannondale have taken its OutFront geometry and Ai rear triangle, and tweaked it to create what they claim is “lighter, smoother, more capable and flat-out faster than any other XC race hardtail out there”, bold claims indeed.
A 69° head angle, extra-long fork offset courtesy of the Lefty Ocho combined with shortened 427mm chainstays is said to provide increased stability on the descents whilst maintaining snappy acceleration for hard, out of the saddle efforts and nimble acceleration when the trail points upwards.
5. Room for Bigger Rubber
An asymmetrical rear triangle, combined with super short 427mm chainstays means that the 2019 F-Si has clearance for 2.35” tyres. That’s trail bike territory, and should allow riders even more flexibility when fine tuning their XC set-up.
Such clearance is not without compromise though, and Cannondale use their own offset chainring and re-dished Boost rear wheel to allow such a feat.
6. A Faster Kind of Thru-Axle
Using the new Mavic SpeedRelease dropout design in the rear means that, much like a quick-release skewer, the axle can stay in the hub for quicker, easier wheel changes. Compatible with standard 148x12 hubs, its bang up to date with modern axle standards too.
Up front, Cannondale have gotten equally as tricky and provided a quick release for the front brake, solving a long-standing issue with the Lefty design.
7. Collarless Seatpost for a Compliant Ride
Cannondale have outfitted the F-Si with a collarless 27.2mm seat post, lowering the clamping point so that more of the post can flex when riding seated.
SAVE Micro-Suspension also aids in seated comfort by allowing the rear triangle to flex vertically for increased shock absorption. In addition to this, Cannondale claim that a directionally optimised carbon layup in the seattube allows controlled bowing for more control.
8. Lefty Ocho: World’s First Single Crown, Single Sided Fork
Arguably the defining feature of the new F-Si is the all-new Lefty Ocho front fork, The world’s first single crown, single sided fork. Cannondale claim the new single-crown design shaves over 250 grams off the previous Lefty Carbon, making it one of the lightest suspension forks available. Not just a fair-weather featherweight, the Ocho is also said to be stiffer than its predecessors too.
9. Lefty Ocho: Smooth as Butter
Cannondale claim the Ocho is peerless when it comes to smoothness. With the fork telescoping on a three-sided needle-bearing where other forks slide on plastic bushings, and with fewer seals, such a claim is quite understandable. Additionally, Cannondale says the new fork offers up no shuddering under load to provide a controlled ride.