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Pinarello Dogma K8-S review

25 Jan 2016
Verdict:

Pinarello has brought back rear suspension to race bikes with the Dogma K8-S, and this time it might just work.

Price: 
£7,799

There are no boring bikes in Cyclist, but only a few can make the claim to be truly exciting. The Pinarello Dogma K8-S is exciting. It’s championing a concept on road bikes that’s had varying degrees of success over the years, but if it proves to be a winner this time you could see many of the big brands launching their own versions. It’s a bold move that has reignited an old question: does suspension belong on a road bike?

RockShox suspension forks were used in Paris-Roubaix back in 1992, and in 1995 Johan Museeuw rode the same race on a full-suspension Bianchi, which offered 5cm of vertical travel. Pinarello’s latest attempt is a little more understated, comprising a compact suspension unit at the top of the seatstays dubbed the DSS 1.0 (Dogma Suspension System).

Pinarello Dogma K8-S suspension

‘Current road bikes are becoming stiffer and stiffer and the result is a lack of comfort,’ says Massimo Poloniato, R&D engineer at Pinarello. And while the K8-S might seem like a specialist build for the demands of the cobbled Classics, it is being touted as perfect for riders looking to do long endurance races or sportives. 

‘We must consider that this bike is not intended only for the pave but it gives more comfort on all surfaces, even on standard roads,’ says Poloniato. Perhaps, then, it has the potential to make a WorldTour bike accessible and desirable to the amateur masses.

Spring in its step

I’ve spent a decent amount of time riding both the Pinarello Dogma 65.1 and the Dogma F8, the last two versions of the Dogma to be released. Both used Toray’s exclusive (and expensive) T1100 1K carbon fibre in places, and there is no doubt that the material contributes to the stiffness of both bikes. But while the 65.1 did an incredible job of combining lateral stiffness and comfort, the F8 was faster and harsher, making it a bike better suited to road racing than long relaxed days in the saddle. The K8-S potentially promises the same aerodynamic and rigid performance benefits of the F8 but with much improved comfort. 

The DSS 1.0 is a simple suspension unit containing a basic elastomer (essentially a rubber bung) that squeezes and expands with the movement of the back end. It offers up to 10mm of travel, but you’d probably only experience the full extent on big impacts such as the cobbled roads of Roubaix. The amount of travel over bumps on a more average ride on tarmac would be nearer 4mm. That doesn’t seem like a lot, but it’s enough to make the K8-S feel like a very different beast to its F8 sibling. 

Pinarello Dogma K8-S rear suspension

While the F8 is quite harsh to ride, it compensates for this with incredible stiffness, supreme accuracy and an impressively low weight given its aerodynamic merits. With the K8-S, those desirable features have, somewhat miraculously, been preserved.

The K8-S has a few subtle geometry tweaks compared to the F8. ‘On the front triangle, following the experience with the old DogmaK we revised the head tube angle and the fork rake,’ says Poloniato. The head tube angle has been made steeper and the fork rake has been increased, meaning that the trail of the bike has been reduced. For anyone bamboozled by talk of trail and rakes, it basically means that the steering has been made deliberately twitchier, which is somewhat surprising as one might have expected a cobbles bike to go for a longer trail for increased stability. However, Pinarello has lengthened the chainstays to allow for the extra flex at the rear, which has extended the wheelbase, which in turn creates added stability. So I theorise that the changes to the head tube and fork are aimed at bringing the handling back into line with F8. 

It works. From the first time I stood up and sprinted on the K8-S, I felt hopelessly infatuated. It’s a rare and enticing combination of rugged stiffness, acute handling accuracy and comfort that makes it feel as if it’s floating above the road.

Pinarello Dogma K8-S bottom bracket

At the front, the K8-S still has the rigid and firm feel of the F8. When you hit a bump the details of the impact are transmitted in high defintion straight to the handlebars, but at the rear the suspension moderates the forces that travel up to the saddle. As impacts increase in force, the buffering becomes more apparent, clearly working to the full over jagged harsh cobbles where the complete range of travel comes into effect and protects the rear end of the bike (and rider) from disturbance. That said, the separation between the front and rear of the bike is actually less than I would have expected.

The DSS 1.0 may be at the rear, but bumps at the front will still cause the frame to flex, bringing the suspension system into play. It’s this difference that separates the K8-S from that other big player in the suspension endurance bike market – the Trek Domane. Trek’s IsoSpeed decoupler system uses a pivot at the seat tube junction with the top tube to isolate the rider from the rest of the system. 

Pinarello Dogma K8-S review

When you hit a bump the IsoSpeed means your backside is cushioned but the front remains rock solid, so you feel the impacts through your arms. With the DSS1.0, the front triangle and rear triangle flex slightly towards one another. That means that there’s a little more balance between front and rear than might be experienced with other suspension systems. 

To my mind, the IsoSpeed system does ultimately offer more comfort at the back end, but the Pinarello manages to feel essentially racier – more in line with my expectation of how a race bike should feel. 

The K8-S is certainly a comfortable bike, but is it a better option than the F8? Well, the simple answer is yes – for most people. I still prefer the F8, simply because I am prepared to forgo comfort for all-out speed and slightly sharper handling. But, in truth, the difference in performance between the two bikes is very small, and the inclusion of the suspension system opens up a realm of possibility for where this bike can be comfortably ridden, and who can ride it. 

Spec

Pinarello Dogma K8-S
Frame Pinarello Dogma K8-S
Groupset Shimano Dura-Ace 9000
Brakes Shimano Dura-Ace direct mount
Bars Most Jaguar XA
Stem Most Tiger Ultra 3K
Wheels Mavic Ksyrium Pro Exalith
Saddle Fizik Arione k3 Kium
Contact yellow-limited.com

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