FSA sheds weight with their latest KFX mountain bike crank sets by machining, then bonding an interlocking two-piece design that promises a boost in stiffness & strength. But light hollow alloy cranks aren’t all they have in store this year. There’s also an extended AGX gravel bike cockpit line with aero bars & a new dropper, plus more internal cabling options and Super Compact power metering…
FSA KFX light hollow aluminum mountain bike cranks
FSA’s latest top-tier mountain bike cranks are set to leave carbon behind in favor of a new two-piece machined aluminum design. The new KFX alloy cranks take K-Force to a next level, promising a better blend of lightweight and durability vs. carbon. While FSA says they won’t be replacing carbon mountain bike cranks entirely, these do look to be even lighter.
With a modular, spiderless design, each KFX crank arm starts out as two separate forged blanks. Then precision CNC machined into two pieces, the hollowed out halves feature a series of three main ridges & grooves down the outside of each arm that form a tightly interlocking single piece.
FSA then bonds the two halves together with adhesive to create a lightweight, intricately internally machined & hollow crank arm that they say is much stiffer than any of their previous alloy cranks. FSA isn’t the first to bond together MTB cranks, but their internal machining looks impressive.
Another post machining process finalizes the external shape. Then anodizing & other finishing give you the final look, with the construction method revealed by the seam and interlocking teeth visible along the outside of the finished crankarm.
Final details are still outstanding, buy we do know hat the modular direct mount KFX alloy cranks will hit a premium price point as result of the complex machining and many steps in the manufacturing process. Weight is claimed at just 520g for the modular arms & BB spindle, around 15g lighter than FSA’s carbon K-Force cranks.
The cranks will use a 30mm spindle and be available with modular 1x or 2x chainring setups. Single rings are set to range from 28-38T and doubles including 24/34, 26/34. 26/36, 24/38 & 28/38, with 12-speed compatibility for everything from lightweight cross-country to gravity-fueled enduro.
KFX cranks are expected to be available at the end of summer 2019. They will not replace FSA carbon K-Force cranks which will carry on as well.
AGX gravel or drop bar adventure bike cockpit family
Designed for everything from all-road to gravel to bikepacking, FSA’s Adventure Gravel Cross series of components are all about mixing aero road performance with off-road trail capabilities. FSA seems to position it for any drop bar adventure riding, and is intended to be the ideal fit to a K-Force WE Disc brake electronic groupset.
K-Wing AGX aero carbon gravel bar
Aero gravel means mixing comfort control & sleek bar shapes. The K-Wing AGX hits all of those with an aero shape that rises next to the stem then curves down as the tops move out to offer a bit of give to damp impacts from rough roads. The bars also get an ergonomic divot at the bend for a comfortable place to rest the pads of your thumbs for longer periods of time.
One defining feature is probably the 12° flared drops that add 5cm width to the 40, 42 & 44cm options (measured c-c at the hoods). The UD carbon bar gets a 31.8mm clamp, a compact bend with 115mm drop & 75mm reach, and is wired electronic ready for Di2 or FSA’s own WE.
A-Wing Pro semi-aero aluminum gravel bar
There’s also a more affordable alloy version called the A-Wing Pro with much of the same shaping, minus the divot at the bend. The alloy bar uses a 15° flare to get similar 50mm extra width at the drops. The A-Wing Pro will be offered in wider 42, 44 & 46cm widths (c-c at the brakes), and an ever so slightly deeper 118mm drop/78mm reach.
Flowtron AGX dropper seatpost
Essentially an adapted lighter weight version of their recent Flowtron MTB dropper post, the new Flowtron AGX scales things back to fit gravel & adventure bike post sizes, with shorter travel and internal routing. The AGX dropper will be offered in 27.2 or 31.6mm diameters with 70mm of drop. The gravel-ready dropper needs just a minimum of 100mm insertion, and features a zero setback design with separate two-bolt rail clamp & a single bolt angle adjustment head.
FSA ACR aero stem with internally routed cabling
Continuing down the integrated aero setup pathway, FSA’s new ACR aero stem offers more cockpit flexibility and bar adjustability while retaining that neat no-cables look. Designed to be a modular ‘plug & play’ solution for bike makers, bar height can be easily adjusted with special openable spacers under the stem, and riders can still dial in the tilt position they want at the bar.
The Aerodynamic Cable Routing (ACR) system is designed to offer bike makers the option for a clean, fully internal routing setup that works with mechanical or electronic shifting and rim brake or hydraulic disc brakes. Paired of course with the ACR headset all four cables stay inside the bar to the stem to the frame or steerer tube, without a limit on bar rotation like in some competing systems. FSA has a sizable footprint in the OEM market, so the addition of a standalone stem should increase the likelihood (and lower the price) of getting a full internally routed cockpit on your next new bike (sorry to all the bike mechanics who will have to deal with setup, adjustment & maintenance.)
We first got a look at e FSA’s aerodynamic integrated ACR setup on their one-piece Vision Metron bar+stem at Eurobike last summer. But now the aero separate stem will make setup and adjustability much easier to manage, and will work with a wide range of modern internally routed handlebars.
FSA PowerBox Carbon power meter cranks
The PowerBox road power meter crankset is one of the few spider-based measurement options available for gravel & adventure friendly low gearing. FSA’s Super Compact takes premium powermeter chainring sizes to an all-time low with the option for 48/32 or even 46/30 rings. There’s still the option for more conventional 53/39, 52/36, or 50/34 rings for road as well, as are TT versions with 55, 54 & 42T chainrings available. Interesting news, top-level PowerBox Carbon cranks will now have all of their measurement & reporting functionality unlocked when you get them, unlike previously where you could buy the cranks at a low initial price (or have them come stock on a bike) and would then have to pay FSA an additional fee to ‘unlock’ their full power metering capabilities.