Cervélo S5 review: Crazy fast, but not a bike I’d want to own

It’s worth bearing in mind before you embark on this review that the Cervélo S5 is now three years old, and in bike development terms that means it’s probably due an update this year or the next. Why bother reviewing what might soon be an outdated model? Well, according to our own wind tunnel testing the Cervélo S5 is still absolutely one of the best aero bikes on the market. The fastest, at zero yaw, even compared against far newer bikes like the Specialized S-Works Tarmac SL8 and the Factor Ostro VAM. 

It is also still being used at the highest level of the sport, and when a new model eventually replaces it, the older model will then likely go on sale, and might become a more attractive proposition for a would-be customer.

With such a winning record, is the Cervélo S5 one of the best road bikes on the market? Yes, absolutely. But that doesn’t necessarily mean I think you should buy one. I’ve been riding the lowest tier option, with a £9.5k/$9k asking price, and equipped with SRAM Force, an included power meter, and Reserve wheels. 

After plenty of miles of varying terrain from flat blasts to intense, steep climbing, I’m impressed in many ways, but despite it being demonstrably quick it’s not a bike I’d particularly relish owning. It might be the bike of your dreams though, so you may as well keep scrolling and see what's good and what’s not so good. 

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Design and aesthetics

In a world where all aero bikes basically look the same, I must say it’s refreshing to have an all-out aero machine that still has a distinctive look about it. You’d be hard-pressed to find that cockpit and that heavily sculpted seat tube (if you can even call it that) elsewhere. It’s not necessarily to my liking. It looks a little too robotic, compact, and somewhat inelegant, but beauty is in the eye of the beholder and ultimately this is a bike that’s about speed over visuals. 

Up front it’s easy to forget quite how outlandish the design is. While a hinged fork isn’t new it’s certainly still extremely unusual, and even amongst time trial bikes it’s not the norm. It means the head tube is incredibly narrow, primarily because it no longer has to house bearings large enough to fit around a traditional 1 ⅛” steerer tube. 

The head tube of the frame itself is relatively deep, not to quite the degree of the crazy new Ridley Noah Fast, but when bolstered with the external hinge of the fork it makes for a very long, very narrow front end. The fork even juts out somewhat at the head tube hinge, in the same way as the head tube on the Pinarello Dogma F or the S-Works Tarmac SL8 does. 

The Y-shaped cockpit was relatively groundbreaking at the time, and has since been co-opted in various ways by the likes of the Bianchi Oltre and the Colnago Y1Rs. It may look like it adds a whopping amount of stack to the front of the bike, but essentially it puts the handlebars in the same place as a traditional stem would. It’s modular, so the bars physically bolt onto the Y-shaped struts, and so to change the width (from 38cm to 44cm in 2cm increments) you ‘just’ unbolt the bar and swap a new one in (and do all the hoses and cables). There is 5º of rotation in the cockpit, as the mounting interface is gently curved, so while it looks more complex than a one-piece system, it is more tunable than the cockpits of most race bikes nowadays. 

The main triangle is comprised of very deep, very narrow tubes. On the down tube and heavily curved seat tube there’s just enough width to mount a bottle and no more. Handily there is a triple set of bosses on the down tube, meaning if you only want to run one bottle you can have it even lower, or the higher position for a pair. 

At the back end, the curved seat tube hugs the rear wheel more than any other bike I can think of, before veering hard into a near-vertical, very deep seat post that is absolutely unyielding. At the base of the bike, the bottom bracket is hefty, almost clearing the top of the big ring of the chainset. 

The wheels, as you’d expect on a bike this aero, are the pretty deep Reserve 63/52 (comfortable mid-pack in aero terms according to our own wind tunnel testing), with a 25mm/24mm front/rear internal width. This is pretty wide, especially for a bike this old, and it may surprise you to hear that the Cervélo S5 can clear a 34mm (measured) tyre. This is a good thing, not only because we’ve shown that it’s probably faster for most people, but it’s also more comfortable for what is quite an unforgiving ride. 

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Performance

Hopping onto the Cervélo S5 from basically any other bike is like switching from your old CRT television to a 4k IMax movie. You feel absolutely everything, mostly through your perineum. On a standard bike design, where the seat post is cantilevered rearwards to a far greater degree, the amount of compliance it can offer is often the majority of what we think of as ‘rear end comfort’. On the S5, where the seat post is extremely deep and essentially vertical, there is scant comfort offered at all. This may not matter to the pros, but to you it might. 

It initially had a set of 28c Schwalbe Pro One tyres fitted, but after a couple of rides I swapped them out for a set of 28c Continental GP5000 S TR, the fastest road tyre on the market according to our own lab testing. In reality, if I was running this bike long term I’d go for a 30c at least, if not wider given that we've proven that wider tyres are faster for almost everyone. It can take it, there’s so little drawback to doing so, and it would have huge comfort implications. Luckily the wide internal width of the rims means the 28s plumped up well in any case. 

Before we get to the ride I actually want to say I really like the cockpit. Yes it looks complicated, but upon receipt of the bike it had a deafeningly loud creak from somewhere in the bowels of the head tube, and so I took it all apart, regreased everything, and put it all back together again with very little fuss. You can adjust the spacer stack too without having to cut your steerer, which genuinely is a bonus if you like to mess around with your fit. Yes, routing the hoses may be a nightmare, but it’s a nightmare on any integrated cockpit. At least here you get some adjustability. More than that, the bar shape is brilliant, with a lovely long final section to the drops for clinging onto while impersonating a diesel train with your nose in the wind. 

Anyway, comfort issues aside, there’s a lot to like here. The Cervélo S5 is sickeningly fast. On flat and rolling terrain, for which it was primarily designed, it absolutely barrels along. I’m never going to claim that I can feel the aero differences between a few top-end bikes, but the S5 does, it must be said, have a purposeful, almost TT-esque feel to it. You want to sit either in the drops, or in an aero position on the hoods and urge it to tick along at full chat. 

Oddly though it doesn’t feel fast. It is fast, very very fast, but in many ways, it feels quite pedestrian, with a solid, stable ride that at times verges on being a little languid. It’s never a bike I relished riding on twisty, winding descents, lacking the responsive front end of the likes of the Pinarello Dogma F. This goes totally against the geometry charts, with the S5 having a steeper head tube, shorter chain stays, and a lower trail fork than the Dogma F, but the Italian bike did feel more lively. As ever, geometry charts can only tell you so much. 

Part of it I suspect is weight, with the S5 weighing 340g more than a similarly-specced Trek Madone, but part of it I think is just the bike being absurdly stiff and lacking any of that intangible elasticity that can bring a bike to life. 

If you’re into sprints, uphill or otherwise, the S5 will be your friend. The drops on the bars help a lot, but the whole package is so stiff, especially at the rear end, that you don’t feel like you’re wasting a single watt. It’s magnificent in this respect, and I suspect, as with many other parts of this bike, it was designed not with consumers in mind but with professional racers. 

On longer climbs it feels far less at home. It’s no slouch, don’t get me wrong. It’s a nine-grand superbike that, in the grand scheme of things, weighs very little, but ultimately the characteristics that are often ascribed to bikes that ‘make you want to dance on the pedals’ are absent here. It lacks that easy, whip-sharp acceleration that truly lightweight bikes have on the steepest ramps, preferring instead to muscle over lumps where possible, and settle into a steady, seated rhythm on those that it can't. 

On open, flowing descents it’s remarkably stable, and relatively unperturbed by crosswinds compared to some aero bikes I’ve ridden. On longer bends where you can really pick your line in advance it’s very pleasant indeed, in contrast to how it behaves on tight, twisty roads. If you live anywhere with broken tarmac then larger tyres are going to really help here too, not only in the grip stakes but also to reduce that sketchy chatter that any stiff chassis can impart. 

The groupset is starting to look a little tired now though, even accounting for the fact that it includes a power meter. The difference in feel and ergonomics between the current SRAM Force and the new Red is huge, and with a new Force having already been leaked it's safe to say that this is somewhere I'd happily see the bike updated. Force simply doesn't shift or stop as well as Ultegra, and the ergonomics aren't as good either in my book. 

Value

If speed is your goal then you really are going to struggle to top this I think. In a dead straight line this is as aero as bikes get, even with a second tier groupset, all for ‘only’ £9.5k/$9k, which is a lot of money but a few thousand shy of top-tier race bikes. Yes, you can get the S5 fitted out with Dura-Ace or Red, but that’s a different proposition. 

If you’re racing (and I mean actually, competitively racing, not just the occasional KOM hunt) then it’s a really compelling offering. It looks a bit mad but I don’t think it’s any harder to live with than any other bike with an integrated cockpit. If you’re into sprint triathlons it probably makes a lot of sense too. For longer events, Cervélo has stopped making its own TT extensions kit for the bike, but aftermarket options are available, and if you can’t stretch to a full TT bike then having one of these and some bars is a pretty decent compromise. 

If performance is your goal then absolutely it represents decent value, especially if you’re reading this long after publication and it’s now on sale, but as a bike to own and just ride around on with your friends, I’m not so sure. 

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Verdict

By the numbers the Cervélo S5 is a pretty brilliant bike. It’s supremely aerodynamic, monstrously stiff, and the second tier SRAM Force model is actually pretty decent value if you want to go fast. As a riding experience though it is so single minded in its search for speed that it seems to be left lacking in the joy department.

If you want to win a bike race then this is ultimately one of the best options on the market still, even given how old the bike is (even more so when you consider the current S5 only received modest tweaks over the old version). 

If, however, you want a bike that’s a joy to ride and own then I suggest you look elsewhere. It’s so stiff, and almost robotic at times in the ride feel that I never really lusted after my next ride on it as I often do with other really posh bikes.