Fit & Features
A common denominator among carbon-plated trail shoes, at least the ones I’ve reviewed, has been their rigidity. From a propulsion standpoint, this makes sense. Maximum energy return is bolstered by having a shoe that acts as a stiff lever, and the inflexibility of performance plates provides that — but almost always at the expense of ground feel. Recognizing the value of ground feel in the context of trail running shoes, footwear brands have experimented with the design of their carbon plates, to mixed results.
Perhaps the most successful take comes from Carbitex, a company that makes flexible composites for myriad brands in the outdoor industry, including Speedland, Saucony, The North Face, and now Scott. Their recently released “GearFlex” carbon plate, which is featured in the Ultra Carbon RC, is unique in that its degree of stiffness (reportedly) responds to speed. At slower paces, the plate retains its flexibility, but once the intensity picks up, it becomes more rigid. Theoretically, the plate’s flexible property should allow for more stability on technical terrain where most folks will be forced to slow down. Scott also decided to shorten their plate, giving it a “swallow tail” shape that splits under the forefoot and toward the heel to boost lateral flex.
The Ultra Carbon RC’s Carbitex GearFlex carbon plate is just one part of deconstructing the shoe’s midsole. Scott also enlists their “Evolved Rocker 2” platform, designed to reduce heel striking and increase running efficiency, and their premium “Kinetic Light Foam,” a fairly dense material that gives the shoe its 25 mm / 20 mm of stack height. This arrangement (i.e., dynamic carbon plate, significant rocker geometry, and relatively hard midsole foam) is new to me, and after a few brief runs, I’m still having trouble finding appropriate models to compare the Ultra Carbon RC to. Whether that portends well for the shoe remains to be seen.