Specialized had two key goals in mind with the new shoe; to increase comfort and improve the stiffness. Feedback from customers led to a focus on improving the comfort, while its many sponsored pro cyclists, like Peter Sagan, wanted more stiffness when they're putting out considerable power.
First, that focus on comfort. The S-Works 6 could hardly be described as uncomfortable, but Specialized has made a few interesting changes to the new shoes. There's a wider heel cup intended to provide a more comfortable grip on the back of the foot whilst also minimising heel lift. Volume has been increased in the midfoot and toebox areas, there's a new padded tongue with an off-set closure and offset dials to reduce pressure across the top of the foot.
The Dyneema Mesh upper has been refined with a one-piece construction to eliminate stitching. It's a material that is sandwiched between a four-way stretch mesh and TPU to provide areas of no-stretch to deliver a very secure fit.
And there are all-new Boa S3 dials, the most noticeable change in the new shoes. These new dials are exclusive to Specialized and have an all-metal CNC machined construction for extra durability and feel much nicer and slicker to operate, with micro adjustments to tighten or loosen. They're quieter too. The Boa dials are now offset across the top of the shoe to better spread the pressure. They're also bonded to the shoe to further eliminate discomfort.