Though it may not look like it, your bike’s chainset probably accounts for around a tenth of its total weight. The K-Force Light BB386EVO is the latest top-end chainset from Taiwanese component giant FSA, featuring hollow carbon arms and 10/11-speed compatible chainrings. Our 50/34 version, with 175mm cranks, weighed 572g plus bearings.
The K-Force Light’s spider appears superficially similar to the four-arm offerings from Shimano and Campagnolo, and like them FSA has moved to a single bolt circle diameter (110mm) for all sizes of chainring.
Take a closer look, though, and there are five T-30 Torx aluminium chainring bolts that thread in from the inside, the fifth hidden behind the crank – all in the name of stiffness. The design is otherwise conventional, with a 10mm self-extracting crank bolt holding the whole assembly together, and a wave washer to preload the bearings.
Thanks to the concealed bolts, the outer chainring blends neatly into the carbon spider. The back is heavily machined, with pronounced shifting ramps, strategically placed pins and weight-saving cutouts.
We fitted the K-Force Light to a Shimano Ultegra-equipped Scott Addict with a BB86 bottom bracket shell, which put up some resistance – this is highly installation-specific though. On the road, there was a small but noticeable increase in stiffness under power over the Shimano crank, with shifting as good as ever.
A chainset is one of those parts that generally only impacts significantly on your riding if something goes wrong, and the K-Force Light has been without issue, bar some marring of the finish from our tester’s heels-in riding style. For this reason, we’d favour the all-black version.
Should you buy one? If weight saving is your goal, this is a quality piece of equipment; there’s zero performance cost to the lightweight design. At the list price it’s eye-wateringly expensive, but shop around and you may find a more realistic price.