[This article was last updated on November 7, 2017]
Ever more manufacturers are adding features to road bikes to deal with bumps and vibration. Here’s a look at the technology that’s out there to help you make the right buying decision.
We’re not talking about suspension when it comes to road bikes. At least, not suspension in the mountain bike sense with several inches of travel at both the front and rear. No, when it comes to road bikes we’re talking about design features that are intended to soften the ride just a touch.
Why would you want that? First of all, for comfort. Everyone wants to feel comfortable when they’re riding their bike, right? Life’s just better that way.
Second, you can have more control over your bike if you’re not being jolted around or bounced out of the saddle. As well as adding safety, that can lead to increased speed: “smoother is faster”, as Specialized is fond of reminding us.
Third, and kind of related, all those little bumps can gradually lead to fatigue over the course of a long ride, sapping your energy.
So what bump-taming features are out there?
The Pinarello Dogma K8-S features what the Italian brand calls a DSS 1.0 shock between the seatstays and the seat tube, with travel that relies on flex in the chainstays.
According to Pinarello, “The Dogma K8-S is the result of a specific request of Team Sky: to have an innovative frame able to reduce the psycho-physical stress of the athletes, and thus increase the performance in the Hell of the North [the Paris-Roubaix cobbled classic].
“We designed a lightweight suspension system in combination with the new carbon chainstays, able to flex, in order to create a pivot point for the perfect riding comfort.”
One of the road.cc team got the chance to ride on the Dogma K8-S and found that it does do what Pinarello claims. The Dogma K8-S smooths over bumps, holes and the occasional bit of mud, not at the front, obviously, because there’s no suspension in the fork, but the ride is appreciably softer at the back.
It’s the difference between getting shaken up and down in the saddle on a gravel road (we couldn’t find any cobbles), and feeling more comfortable and in control. Significant.
We’d say that this type of suspension is really only suitable for something like cobbles (which, as mentioned, is what Pinarello have in mind) or gravel roads. It would be overkill for decent Tarmac.
Trek has been including an IsoSpeed decoupler in its Domane and Silque endurance bikes for a couple of years. In 2016, Trek turned it up to 11.
What the hell is an IsoSpeed decoupler? If you have a couple of minutes (1:45mins, to be precise), this video from the time it was launched tells you everything you need to know.
In short, the seat tube isn't welded to the top tube/seat stay junction. The IsoSpeed itself consists of a bearing on either side, with a bushing forming the mechanical attachment between the top and seat tubes; this allows the whole length of the seat tube to flex under load, reducing the amount of road shock that gets transferred up to the rider.
When we reviewed the aluminium 2014 Trek Domane 2.0, we said, “On the road the compliance arising from that flex was noticeable – sometimes. We found that the frame's small bump sensitivity was not much different from other sportive or comfort bikes. However, when the going got even rougher – like on big potholes or really rough unpaved tracks akin to the cobbles of Flanders and Roubaix – the frame came into its own a bit more, softening the big hits.”
The most affordable Domane with Isospeed in Trek’s 2018 lineup is the £1,000 Domane ALR3. There are cheaper Domane models, but they don't have the Isospeed decoupler and we think Trek is a bit cheeky to bill them as Domanes without it. At the other end of the scale there's the £10,500 Domane SLR Race Shop Limited with Shimano Dura-Ace Di2 electronic shifting.
Trek has transferred the IsoSpeed decoupler technology over to the Madone 9. You don’t get as much movement at the saddle as you do with a Domane but the difference from a standard road bike is appreciable.
We said, “If you're familiar with riding a full suspension mountain bike, it's nothing at all like that. Not in the same county. But the IsoSpeed system does smooth over the lumps and bumps to an appreciable degree. The effect is subtle, but it is noticeable.”
The problem is, the cheapest Trek Madone 9 Series bike, the 9.2, is priced at £4,800. Look away if you're of a squeamish nature....the top model Race Shop Limited will set you back £11,500!
Lapierre incorporates an elastomer into the top tube of its Pulsium endurance bike that’s designed to improve comfort.
The elastomer comes in the form of a ring in the lower of the two joints between the top tube and the seat tube. Lapierre says that it acts as a shock absorber to dampen vibration from the road. The frame’s carbon-fibre layup is also designed to absorb shocks and vibration.
Lapierre says that the curved top tube flexes more easily than a straight one while the curved and narrow seatstays act like leaf springs for better impact and vibration absorption at the back end.
“It does actually smooth out the bumps on washboard surfaces and broken tarmac with very little in the way of spongy rebound when it's not wanted,” said our reviewer Stu Kerton. “The upper section of top tube works like a brace especially for the lateral forces from pedalling and cornering. A few times you put the hammer down and it feels a little soft but that's few and far between.”
Lapierre offers 2 versions of the Pulsium starting with the £2,099.99 Pulsium 500 with a Shimano 105 groupset.
Specialized's Roubaix endurance bikes feature a fork shock absorber they call Future Shock and — on the high-end models — the CG-R seatpost.
Future Shock is essentially a spring inside the headset that allows the bars and stem to move up and down. There are interchangeable springs for riders of different weight. It can give up to 20mm of travel.
Bianchi has taken a totally different approach with its CounterVail Vibration Cancelling Composite Technology, or CV for short.
The CV is a viscoelastic material embedded within the carbon layup of certain areas of the frame. Bianchi claims it has 75% more vibration-cancelling capacity than other (traditional, if you like) carbon frames.
CV isn’t designed to deal with larger bumps – it is by no means a suspension system. Rather, it is intended to damp the high frequency vibrations that you get from a typical road surface, and the effect is subtle.
Bianchi says that the key benefits to using CV are reduced muscle fatigue and increased energy savings, improved handling and rider control, and increased rigidity and peak power output over long distances.
Bianchi first introduced CV on its Infinito CV endurance bike, and has since used it on the Specialissima lightweight race bike.
The claims might sound like PR hocus pocus but when we reviewed the Bianchi Infinito CV we said, “You still get plenty of feedback from the road surface through the controls, but the CV simply removes the harshness, damping the vibrations and delivering a smoother ride.
“The benefit of the CV technology is that it's always working. Even out of the saddle on the climbs, the frame is muting vibrations. An area where the CV really shines is on fast and steep descents with an unpredictable road surface.”
We were so impressed that we made the Bianchi Infinito CV our road.cc Bike of the Year in 2013-14.
Loads of bike manufacturers say they make their seatstays flexible so as to provide plenty of comfort. That’s often just a case of making them skinny and thin walled, although some brands go further.
Volagi, for example, uses what it calls Longbow Flex Stays “to isolate the rider from harsh road vibrations and impacts and provide up to 6mm of movement at the saddle”.
We reviewed the Volagi Liscio frameset here on road.cc and said, “The Long Bow flexes just enough to take the sting out but not to the extent you feel any loss in the performance stakes.”
Merida uses Flex Stays on many of its bikes, where “the profile of the seat and chainstays and the lay-up schedule of the carbon [are adapted] so the rear end works like a flat spring, absorbing surface bumps and reducing vibrations”.
Many other brands do something similar although Merida is unusual (but not unique) in that it also incorporates organic flax fibre between the individual carbon layers, the idea being to filter high frequency vibrations. It’s used in the Ride 5000 that we reviewed here on road.cc, for example, and also in the lightweight Scultura.
Cannondale uses what it calls Save Plus features on its Synapse endurance bikes. There are several aspects to Save Plus, one of the claims being that the seatstays bend and compress under load like a spring.
Cannondale also says, “The Synapse's carbon layup was designed to maximise something called ‘inter-laminar shear dissipation’. Basically this means that the fibers are oriented in such a way that vibrations get caught up in the layers and are diffused before they can make it to rider. This helps tune out that energy-sapping road buzz and keeps you fresher.”
A slim seatpost provides more movement at the saddle. Cannondale goes super-skinny at 25.4mm, but don’t underestimate the difference a 27.2mm seatpost can make over a 30.8mm, for example.
When we reviewed the Cannondale Synapse Carbon Ultegra Disc we said, “It's smooth enough for the harshest roads and comfortable for the longest rides, yet never holds you back when you want to get a shift on.”
Other ways to improve comfort
In this article we’ve concentrated on frame features that are designed to deal with bumps and vibration, but there are many other ways to make your existing bike more comfortable; you can fit wider tyres, switch your saddle, change your bar tape, and so on.
For more ideas on adding comfort go to our article: 9 ways to make your bike more comfortable.
Mat has worked for loads of bike magazines over 20+ years, and been editor of 220 Triathlon and Cycling Plus. He's been road.cc technical editor for eight years, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a past winner of the Cycling Media Award for Specialist Online Writer.