At just 900 grams, the all-new F-Si is the lightest mountain bike frame Cannondale has ever made. It shaves 80 grams off the previous F-Si, and when you factor in the svelte new Lefty Ocho, you save a whopping 330 grams on the frame and fork.

Cannondale's engineers focused on features that deliver real performance benefits out on the course. Features like Ai and OutFront, or improved compliance, or improved durability. That’s what wins races.

Lefty Ocho Fork

The all-new Lefty Ocho is the smoothest, stiffest ultra-light XC fork ever made. It floats through chop and steers through the choss like nothing else.

Silky smooth and unfazed no matter how hard you push it. Happy to get in as deep as you dare. Its extra-long fork offset pairs up with the F-Si’s new, slacker 69° head angle to create OutFront geometry, giving you extra stability to charge the downs, with full XC agility on the ups. Helping the F-Si track perfectly through whatever you throw it into.

Asymmetric Integration Drivetrain Offset

Ai is Cannondale's proprietary Asymmetric Integration drivetrain offset. By moving the gears and rear triangle over, we create space (double what you get from Boost) that enables them to shorten the stays AND still have clearance for big tires and room for 2x drivetrains if you want. It even creates a stiffer, stronger rear wheel by evening out the dish.

Save Micro-Suspension

Save micro-suspension tunes the overall compliance of the frame. The rear triangle flexes vertically for shock absorption. Directionally optimized carbon layup in the seat tube allows controlled fore/aft bowing, for better traction, higher speeds and drastically minimize

For seated comfort, designing the F-Si with a 27.2mm seat post was just the start. The collarless seat post clamp takes it even further, lowering the clamping point so that more of the post can flex. Put the power down all day long, without the punishment.

A Faster Kind of Thru-Axle.

Slotted dropout design lets the axle stay in the hub for quicker, easier wheel changes. Compatible with standard 148x12 hubs.