Cannondale’s flagship hardtail, the F-Si, is available in seven iterations. Each model features a lightweight carbon fiber frame designed for one purpose—to be an extraordinarily efficient cross-country race machine. And for the Cannondale fanatics—we know you’re out there—the F-Si Carbon is even available as a frame only in classic throwback colorways that pay homage to the brand’s legendary race teams of the mid-’90s. Complete bikes range from $2400–$11,000.
“The F-Si Carbon frame offers ample tire clearance to shed mud and debris.
The F-Si frame is a beauty, with its sleek contours made from Cannondale’s proprietary Ballistec carbon composite. The chassis is stunningly smooth from tip to tail, thanks to internal cable routing that conceals derailleur cables, housing and the rear brake’s hydraulic line.
Where the seatstays meet the seat tube is where the F-Si is most visually stunning. Its straight-legged, asymmetrical seatstays connect directly to the seat tube, with no support bridge between them, leaving ample rear-tire clearance. Add the integrated seat collar—or lack thereof, as the seat post is tightened via an unseen, internal bolt hidden in the seat tube—and you’ve got a bike with a very modern look that is just plain cool.
Rather than attaching the rear disc-brake caliper to the seatstay, Cannondale chose to attach it to the chainstay via a flat-mount. Not only does it neatly tuck away the rear caliper—nestling it cleanly between the chainstay and seatstay—it also keeps it enclosed and out of harm’s way. The end result is a svelte and stunning finished product that was clearly well thought out.
The F-Si Carbon 3 that we chose can be rolled out of your local Cannondale dealer for $3850. This model comes equipped with SRAM’s GX Eagle 12-speed drivetrain, as well as SRAM’s Level T hydraulic disc brakes with 160mm front and back rotors. Stan’s Neo hubs are laced into Stan’s Crest MK3 rims, which feature a 23mm inner rim width that rounds out a sound XC-specific build.
SRAM’s 12-speed GX Eagle drivetrain delivers performance for a great price.
A flat mount positions the disc brake caliper on the chainstay, tucked away from harm and protected by the seatstay.
Cannondale’s distinct Lefty fork handles direction changes and suspension duties on the F-Si Carbon 3. When the Lefty was first released in 2000, skeptics scoffed at the “half a fork”; however, in the nearly 20 years since, the Lefty has proven as torsionally stiff, and sometimes stiffer, than many high-end traditional forks with two stanchions. Any skeptics should be reminded: the landing gear of 747 airplanes use single-sided fork blades—and Ducati has won championships with single-sided motorcycle swingarms with technology similar to that of the Lefty.
Cannondale’s Lefty fork is unique and performs with precision.
DOWN AND DIRTY
At 23.75 pounds, the F-Si Carbon 3 is lightweight, but not so lightweight that it will make you nervous. Riders looking to shed maximum weight could look into the top-of-the-line F-Si Hi-Mod World Cup, which sheds some weight over our mid-level build. That said, we were never worried about pushing the F-Si Carbon 3 to its limits—the Truvativ Stylo 6K Dub cranks and bottom bracket felt stout and sturdy.
The Cannondale F-Si Carbon 3 comes ready to race right out of the box.
Climbing: The 12mm × 148mm Boost rear-hub spacing helped the chassis remain stiff when hammering out of the saddle. Rather than wrenching and flexing under load, the F-Si was able to transfer power to the rear wheel.
The remote lever that allows the rider to lock out the front suspension on the fly is the F-Si Carbon 3’s best and most effective tool. While many bikes at this price point offer a fork with lockout capabilities, the lever to access this feature is often mounted on top of the fork crown. The lever is also typically much smaller than the under-bar remote button and often requires the rider to take his eyes—and mind—off the trail to locate it. This process can be so distracting that riders tend to avoid using the lockout feature, even when needed, missing out on the opportunity to optimize the bike’s performance. This is not the case with the remote lockout lever; it’s there when you need it. When you are faced with a sprint to the finish, the Lefty Ocho and its remote lockout can’t be beat.
The Lefty Ocho’s handlebar-mounted remote lockout lever can turn the front suspension on and off on the fly.
Up and down the mountain, the F-Si Carbon 3 responded well to rider inputs. We were particularly pleased with the usefulness of the setup guide that Cannondale prints right on the side of the Lefty Ocho fork. The recommended settings are remarkably accurate. Beyond offering a suggested air pressure for all rider weights, a suggested rebound setting is also provided for each air setting. All of our testers were able to follow the setup guide and enjoy precise results.
The Lefty Ocho fork performs well when needed.
The bike performed extremely well under most conditions. The only disappointment was with the SRAM Level T brakes. While the Level Ts were able to provide ample braking power when descending, they offered little modulation, which made the lever pull feel very sensitive. The immediate power was something test riders needed time to adjust to.
MODS AND UPGRADES
Installing a dropper post on the F-Si Carbon 3 wouldn’t be a bad idea. Many of the top World Cup XC racers are choosing the slight weight penalty of a dropper in order to ensure the most control possible on technical descents—and we predict this trend will trickle down to everyday riders over the next few years. Conveniently, Cannondale’s interchangeable routing chips that offer clean, configurable internal cable routing even provide open space should you choose to mount an internally routed 27.2mm dropper post (several companies now offer this size) in the future.
If you’re looking to get your first serious mountain bike, the Cannondale F-Si Carbon 3 should be vying for your attention. Road riders looking to get dirty, look no further. And for seasoned mountain bikers who already own a full-suspension bike but are looking to get a hardtail for short-track cross-country events, the p F-Si Carbon 3 could be a serious competitive weapon.
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