This is Pinarello’s WorldTour-level endurance, fondo, cobble cruiser frameset. The name tells a good part of the story: Pinarello Dogma K8-S Frameset. It’s a Pinarello, one of the most storied names in modern racing. Dogma: a top-of-the-line frameset. K=Kobh=cobblestone. 8 is from F8, their road racing bike. S stands for shock.
Yes. This bike has an actual shock. Dogma Suspension System 1.0 (DSS1.0): an adjustable, elastomer rear shock. It provides 10mm of travel. It sits between the seatstays and the seat tube. Thanks to their manipulation of carbon-fiber, there is no pivot on the chainstays. Pivots add weight, complexity, and often reduce torsional rigidity. These stays are merely flattened to maximize vertical flex; the bonus is how they nearly eliminate energy sapping lateral flex.
To further the rough road-worthiness of the rig, the bike comes with a direct-mount rear brake. The direct-mount design affords more room for big tires, like up to 29mm wide depending on the brand and the rim.
Stepping back from the rear triangle, it might be hard to tell that this bike is the rough road rig of the Pinarello line. That’s a result of borrowing many of the design features of the F8. The K8-S has the aero head tube, the FlatBack tube profiles, the aero seat post, the same bowed fork legs. So much is the same that you might be wondering if it’s the same frame.
It isn’t. The geometry has been tweaked more than adjusted. Portions of a degree slacker in head angle. The fork is 6mm longer. The fork rake is 4mm greater. The chainstays are up to 1cm longer. The seat angle and top tube remain the same. The benefit to all this is a bike that has the comfort of a pave pounder, but the feel of a traditional road racing bike. It’s a heady combination: allowing you to ride faster over the rough stuff, and have more energy for riding fast-and enjoying the benefits of a race bike.
That written, the F8 influence is beyond the geometry. Aerodynamics are important everywhere, save steep climbs. Even at Paris-Roubaix, about 80% of the race is on smooth roads. For pro riders, saving energy on the way to the stones, and having the aero for after the stones is no small deal. It has the potential to be a game-changer.
After all the work with design programs and in the lab, Team Sky was presented with the bikes shortly before they started their spring classics campaign. The team rode the roughest roads they were going to race, just to see if the difference between the F8 and the K8-S could be quantified. As it’s Pinarello and Team Sky, of course it could. The K8-S made them faster and saved them energy. Like an eight percent increase in speed while saving ten percent of their effort. The K8-S frameset has a 95g penalty over the F8. But it still leaves the frame in the sub-kilogram club, 990g, and the rear end compliance meant the team could run higher tire pressure, which would pay dividends on the smooth roads after the hell was dispensed with.
As with most Pinarello’s, this frame comes with an aero carbon-fiber seatpost. It’s 300mm long and can house an electronic-shifting battery. The bottom bracket is Italian-threaded. The headset is included, internal, and a tapered 1 1/8” to 1 1/2”. Cable routing is internal. They also run their 3XAir cage bolt system on the K8-S. Use the lower two for better aerodynamics and weight distribution, the upper two for convenience. Cable routing is internal. Dropouts are carbon.
When you want a fast racing bike with a rear end that can save your back and take the sting off of rough roads, the Pinarello K8-S does the job.