(Image credit: Factor) Factor has added another bike to its gravel range today in the form of the Sarana, which the brand calls a 'race endurance' model. The Sarana joins the race-first Ostro gravel , and the Aluto all-rounder, but this is a bike that, in Factor's words, has been “built specifically for ultra-distance racing, and riders pushing the limit of modern gravel racing.” Article continues below (Image credit: Factor) Plenty of riders are already competing in mammoth events on a range of gravel bikes, some off the shelf, some custom built, what makes the Sarana so well-suited to the task? The latest race content, interviews, features, reviews and expert buying guides, direct to your inbox! Factor says Sarana uses a carbon monocoque frame with a directional carbon fibre layup, which is tubed for “lateral stiffness and in-plane compliance.” The brand told me it had endeavoured to strike a blend between comfort, stability and performance .…