Spin: The Pinarello Dogma K8-S

Pinarello has been making bikes designed for rough roads since “Nani” Pinarello hung up his racing cleats in 1952 and began making frames. Of course, back then, they were just called racing bikes. What is novelty to us—gravel, dirt, cobbles—were just roads in post-World War II Europe and any racing bike had to be able to excel over them. The bikes were longer in the rear, steel’s ability to dampen shock was pushed to the limit, and large-volume tires were the norm. It’s only in today’s hyper-segmented cycling world that a racing bike and an endurance bike or even “mixed surface” bikes are considered different categories.

The Details
With this history, it’s no surprise that Pinarello has thrown its engineering weight behind a bike with serious compliance in the rear. With Trek’s ISO Speed and Specialized’s Zertz, novel solutions are the rage, and Pinarello did two things to create its own novel solution. The Italian manufacturer looked to mountain bikes and leveraged its relationship with Jaguar through Team Sky. The result is the Dogma K8-S, and its standout feature is a 10mm elastomer shock between the seat stays and the seat tube.

This is not a new concept. Moots has had its YBB elastomer shock for many years and Calfee produces a beautifully clean elastomer shock in the rear of its Manta road frames. But it does seem safe to say that, with the help of Jaguar, Pinarello was able to test and fine-tune its shock with an incredible amount of data. The car manufacturer showed Pinarello how to accurately measure and remove vibration at multiple points on the bike over real roads and cobbles.

Bottom Line
Price: $6,250 (frame set plus seat post and rear brake)
Weight: 15.4 lbs (56cm w/o pedals or cages)
Specification: Shimano Dura-Ace 9000, Mavic Ksyrium SLE, MOST carbon bar and stem, Pinarello seat post, Selle Italia Catopuma saddle, Mavic Yksion Pro 25mm tires
More: pinarello.com

Tested versus last year’s Dogma K, which Team Sky rode at Paris-Roubaix in 2014, the Dogma K8-S is 4.6-percent more compliant, but the gains in actual performance, according to Pinarello, were staggering—rider speed was 8-percent higher with 10-percent fewer watts over multiple cobble sections. Pinarello has built preload into the elastomer, with two different elastomers available, so riders of differing weights should be able to get close to these results. With the 1mm O-ring to protect it from bottoming out, effective travel is 9mm with a sag of 2mm to 3mm.

The Dogma K8-S is more than a Dogma F8 with a suspension element sandwiched in the rear. Pinarello wanted the aero advantage the F8 provides, but also wanted a longer, more stable platform; so the wheelbase is a bit longer and the head tube slightly taller, but this is no lazy endurance bike. The head tube is still about 2cm shorter than a comparable Specialized Roubaix. The chain stays also received an enormous amount of attention. Flattened laterally, they are designed to let the shock access its travel, yet maintain later rigidity for power transfer. In addition to aero-tube shapes the K8-S also shares material with the F8—exclusive use of Toray 1100 1K carbon. This helped maintain a lively feel and kept the bike fairly light: 990 grams for an unpainted medium isn’t going to shock anyone, but that does include the 10mm shock.

As one would expect from Pinarello, the bike is very pricey: $6,250 for a frameset that also includes seat post and rear brake. Once it was built with Dura-Ace 9000, Mavic Ksyrium SLE wheels, MOST cockpit and Selle Italia saddle, it weighed a very respectable 15.4 pounds in 56cm.

The Ride
At first, this bike was a conundrum. We expected an extremely smooth ride, a magic carpet akin to an MTB with full suspension. The bike is smoother than an F8 to be sure, but not as smooth as a Domane or Roubaix. The front end lacks the compliance of the rear to feel truly balanced on a very rough road. The geometry is also shorter and more aggressive than a traditional classics bike. Is this a classics bike or not?

As the test continued, venturing off dirt to local crit practices, intervals in the hills and even some sprint workouts, we found ourselves seeing the bike in a new light. It climbs exceptionally well—it’s lively and reactive with instant response on steep ramps. The chain stays, while flexible vertically, keep the bike locked down laterally in big-watt sprints and the front end has the same stiff, precise feel we fell in love with on the F8. During long pulls on the front, the K8-S appears to give up nothing aerodynamically. Downhill, it may indeed be faster than the F8, with the added compliance in back giving the bike a more planted, stable link to the road. Did Pinarello miss on a true classics bike or did Pinarello make perhaps the best all-around bike we have ever ridden? In the end, we have come to a very simple conclusion. We are believers, and we believe that Pinarello has truly created something special with the K8.

The Rider
Not a bike for the classics specialist, but a bike for all-rounders. They can show up to crit practice or climbing days, race their buddies down long, flat roads and crush the rough sections. In the end it will all be done with added comfort and a lot of style.