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Lab: 17.0/20 (.69mm head tube deflection; .68mm BB deflection)
Pedaling Response: 12.0/15
Pinarello’s rear suspension is the attention-grabber, but it’s not the entire plotline of the K8-S. The elastomer-based shock—dubbed the DSS 1.0—definitely adds real vibration control. It offers 9 millimeters of rear travel and adjustable preload. (Frame sizes 50 centimeters and smaller have a softer elastomer.) Despite all of that, the K8-S still delivers the vital road feedback required of a race bike. The road doesn’t disappear; it just gets cleaned up a bit.
What’s initially most striking about the K8-S is its race geometry. Yes, it’s an endurance bike that makes concessions for rear-end flex, yet it also has an aggressive 163-millimeter head tube, 72.3-degree head tube angle, and snappy 415-millimeter chain stays. We’re not sure if it’s a comfortable racer or a race-worthy comfort bike. What we do know is the rear suspension and the flattened stays add heaps of compliance, while the rest of the frame feels like it wants a bunch sprint — as our lab data reveals. We’re talking about a phenomenally stiff bike that doesn’t feel like one in the saddle.
That’s no coincidence. To create this bike, Pinarello basically added rear suspension to the exact same front triangle and 73-millimeter bottom bracket shell used for the Dogma F8, the do-it-all race bike that is Team Sky’s workhorse. The only movement we ever felt in the frame itself was out back. And even then, it was only when we needed it — on rough dirt roads and potholes we aimed for during testing.
While the front end is certainly more chattery than the back, Pinarello does make a concession for comfort with a noticeably bowed fork. The bike perhaps feels a bit unbalanced, front to rear, but we only noticed it on the worst of the rough roads. Steering was predictable enough for a crit racer, so it’s safe to say the fork is plenty stiff laterally.
Unsurprisingly, when we saw that rear suspension unit, we thought, “that’s going to be heavy.” But our 55cm tester was 15.63 pounds out of the box. It was built with mechanical Dura-Ace components, which always produce reliably smooth shifts. But anyone shopping in this price range should consider going with Di2 or SRAM eTap. If you’re building your dream bike, dream big.
Our test model came with Mavic Ksyrium SLE wheels, which are essentially Ksyrium SLS wheels with Mavic’s Exalith 2 brake track that supposedly improves braking, especially in wet conditions. We got a few squeaks out of it, but braking was reliably strong in all conditions. The wheels do flex noticeably under heavy pedaling loads, though. That might help keep things comfortable on rough surfaces, but it’s a drag for sprints and long climbs.
The K8-S is sold as a frameset only, though, so wheel choice will be up to the rider. The frame has clearance for up to 28mm tires, and our hunch is a set of Zipp 303s wrapped in some 26mm rubber would be ideal here.
We’ve also got to give a nod to the aesthetics. There’s a subtle beauty to the K8-S — understated colors and swoopy tube shaping (especially at the seat tube-top tube junction and at the head tube) combine to create an endurance bike disguised as a classic all-rounder.
Component highlights: (as tested) Shimano Dura-Ace drivetrain with 50/34 crankset and 11-27 cassette; Shimano Dura-Ace direct-mount rear brake; Mavic Ksyrium SLE wheels
Weight: 15.63 pounds (size 55cm)