If you are into XTERRA racing or just love mountain biking in itself, the all new 2015 Cannondale F-Si may be the perfect steed for you. Light, agile, fast and a 29er of course. It comes in 4 different sizes and 4 different editions, and the bike's Ai system integration features an asymmetrically offset rear triangle and drivetrain. That offset shifts the rear hub and drivetrain 6mm to the right, and gives the bike ultra short chainstays. And Cannondale says the whole Ai system makes the rear wheel dramatically stiffer and stronger because spoke tension is equal on both sides.

The Cannondale F-Si Carbon 2 basks in the Deer Valley Resort, Utah sun and looks fast just standing still.

Cannondale is well known for the Lefty fork system and owning the fork allows them to build the bike they want without having to adjust to other manufacturers options. This fork is a new Lefty 2.o and has a 55mm offset.

This shot of the front end of the Cannondale F-Si can not be duplicated on bikes without such a fork.

Up close with the seat cluster of this Cannondale.

The view of the non-drive side of front triangle.

The cockpit features Magura brakes and SRAM shifters.

The cockpit of the F-Si looks very clean and refined.

A 1x drivetrain is becoming increasingly popular, plus hey, you got 11 gears anyway. This crank however is needed for this bike with the assymetric rear end.

Fabric is a new brand by Cannondale's parent company and these nice saddles can be found on quite a few high end bikes in the line.

Cannondale says the rear stays feature a Speed Save micro suspension technology thanks to a sophisticated layup and precise tube shapes.

SRAM's XO1 does the shifting duties on this Cannondale F-Si Carbon 2 model.

The Save 2 post is lighter and is said to have a natural spring leaf curve.

Magura MT4 brakes do the stopping with 180mm rotors up front and 160 in the back.

All images © Herbert Krabel / slowtwitch.com