THROWBACK THURSDAY, 2016: PINARELLO TRIES REAR SUSPENSION

If there was ever a great example of how cyclical bike technology can be, the Dogma K8-S is it. The latest bike from the Pinarello family was designed for Team Sky to combat the bumps and hits that the cobbles dole out during Tour of Flanders and Paris Roubaix using a rear shock with 10mm of travel. But, when a brand like Pinarello gives it a try, you can be sure the racing world pays attention. And while Pinarello’s minimal design might just make it the best purpose-built bike for warding off fatigue dished out by the cobbles in Europe, for us the bigger question was how suitable it would be for everyday riders.

THE BIKE
As bold as the K8-S is, it didn’t get there without benefiting from some designs that were already in play within Pinarello’s line, notably the aerodynamic Kamm-tail-style tube shapes in the front triangle borrowed from the F8. The fork rake does increase to provide more stable handling and front-end compliance, along with a head tube that is slightly slacker and taller, resulting in a stack 8mm higher than on the F8 (55cm frame).

While simple in design, and one that was popularized on the XC mountain bike circuit back in the early ’90s, the rear end is what’s radically different from anything that Pinarello has done before. Using a pivot-less mono-shock design with an elastomer spring, the Dogma K8-S features 10mm of travel and adjustability to accommodate a wide range of rider weights (there is a 220-pound weight limit). Adjustment can be done through the preload setting on the shock itself, or by using a different durometer elastomer (two different elastomers are available).

While the shock itself absorbs the hits coming to the rear wheel, it’s the shaping of the chainstays that plays a large part in its performance. The chainstays exit the bottom bracket with a large tube profile to achieve the pedaling stiffness required for such a race bike before morphing into an extremely flat profile by the time they reach their midway point to provide the highest amount of vertical deflection possible.

In addition to the suspension of the frame itself, a different seatpost was also developed that allowed 40 percent more compliance than what’s found on the Dogma F8. Pinarello kept the cross section of the two seatposts the same so that each is interchangeable with the other. Tire clearance is not going to be a problem, since 30mm tires will easily clear in both the front and rear.

In all, the Dogma K8-S weighs a claimed 990 grams for the frame (including shock), only 130 grams more than the F8. The price jumps up by $500 over the Dogma F8 to $6250 for the frame, fork, headset, seatpost and direct-mount rear brake. Our test model equipped with Shimano Dura-Ace 9000 and Mavic Ksyrium SLE wheels weighed in at 15.6 pounds.

THE RIDE
Following the bike’s high-profile launch for last year’s Spring Classics, the Dogma K8-S was immediately in very tight supply, but we were able to nab one just days before the 140-mile Belgian Waffle Ride, which is chock-full of dirt roads and unmaintained pavement that’s not so far off of cobble status—the perfect test bed! One week later came the 125-mile-long Rapha Prestige ride that tacked on an additional 13,000 feet of climbing. In just two rides we netted 265 miles on terrain that was exactly what the Dogma K8-S was dreamed up for. Not a bad way to get in some quality testing.

Like anyone would, we initially bounced up and down, in and out of the saddle, to feel the suspension movement. If you are hoping to find some plush, long-travel feel, then you will be sorely disappointed in the minimal amount of movement coming from the rear end. What we found noticeable is that it’s not what you feel on the Dogma K8-S, it is what you don’t. You don’t feel pedal-induced movement, and you don’t feel the full brunt of the harsher hits, either. The normal vibrations from the road are altogether absent, at least in the rear. Its most notable performance improvement was keeping the rear wheel in contact with the ground when cornering on a chopped-out section of road or—gasp—dirt.

Not surprisingly, this was exactly what we found with the Calfee Manta Pro (page 52) that used a similar monostay suspension design. The biggest difference between the two was the Calfee’s additional (2mm) rear-wheel travel and an overall ride quality that felt more like a bike with active rear suspension. The suspension feel on the K8-S is as subtle as it should be; after all, this is a bike with ProTour origins that was designed to be ridden and raced on the road.

Even though the bike surely made us faster through some of the roughest segments we encountered, unless you’re racing, hunting for a handful of seconds here or there is probably not the priority, but getting through a big day feeling fresher would be higher on the list. We came out of the two biggest rides completely drained, having given everything on the course. We never had any lower-back pain throughout either event, and that’s definitely a rarity to avoid it in such long events.

THE VERDICT
Adventure seekers who want a road bike that’s a smoother, faster ride on rough roads and that’s also capable of fitting big tires (up to 30mm) will find that the Dogma K8-S definitely delivers the goods. With neither a huge weight penalty nor a loss in pedaling efficiency, there’s no reason the Pinarello can’t be a good choice for any and all rides. Still, its true benefits lie when the road veers off the city streets and heads for those less-maintained stretches. The only thing that we can think of to improve upon the design would be disc brakes. Pinarello wouldn’t give us a time frame before we see a disc option, but with the UCI slowly lifting the ban, it won’t be long before Team Sky will be demanding them.

PUNCH LINES
• It’s more about what you don’t feel than you do
• Like all Pinarellos, it comes in a ton of sizing options
• Disc brakes, please!

STATS
Price: $6250 (frame, fork, headset, seatpost and direct-mount rear brake)
Weight: 15.6 pounds Sizes: 44, 46.5, 50, 51.5, 53, 54, 55 (tested), 56, 57.5, 59.5cm

Check out pinarellousa.com for all of the details