Cervélo S5 2019 review

For years aerodynamics just meant riding in the drops. Then it meant cutting off your ponytail and wearing pointy hats.

Then it meant deep section wheels and soon-to-be-banned riding positions.

The common theme was taking things in isolation, optimising parts of a bike or rider without much consideration for the way all these elements interacted.

Then Cervélo came along, and by 2007 it had a life-sized, poseable model of its Team CSC-sponsored rider, Dave Zabriskie.

As the company’s co-founder Phil White told us, ‘We took Dave to this place in LA and had him 3D-scanned. Now we have foam Dave and virtual Dave.’

With foam Dave on wind-tunnel duties, positioned atop whatever rig Cervélo was testing, and virtual Dave doing the same in the theoretical world of CFD, Cervélo was a pioneer of the rider-bike system concept, where aerodynamics is treated as a holistic whole.

With such methods comes this third generation of the S5, a direct descendant of what most consider to be the first aero road bike, the aluminium Soloist of 2002.

And Cervélo has created a marvel, albeit a highly divisive and, in my opinion, brilliantly compromised one.

The S5 smacks you between the eyes like an angry Eubank. The first person I showed it to described it as ‘fugly’.

But, like Chris Eubank, this bike’s eccentricities are its main sell.

For nearly ten grand you want your superbike to look super and, love it or hate it, the S5 looks like the kind of bike that should only be ridden with flames coming out of your shoes.

Each piece segues seamlessly from the last, the frame wrapping around the wheels and rearing up into that stem.

Called to the bar

Instead of the standard-issue single tube, the S5’s stem comes up to meet the bars in a V-shape, with a large triangular gap in between (about which a second friend remarked, ‘Is that where it feeds on plankton?’).

The handlebar sits on top of the V’s prongs and is bolted in position from below.

Cables and hoses run through each prong (in a way Cervélo says improves shifting for mechanical groupsets thanks to the relaxed bends, and makes assembly and maintenance easier), and a shim between the stem-bar intersect means the bar angle can be adjusted between 0°, 2.5° or 5° from the horizontal.

However, says Cervélo, ‘We recommend leaving the bar at 0° to achieve maximum aero advantage’.

Cervélo says that advantage is tantamount to a 42g saving in drag, meaning a real-world saving of 5.5W to the rider.

That’s hardly staggering given that generation two of the S5 saved 28W over the first, which is indicative of how far bikes have come and how hard it is now for engineers to squeeze out further gains.

And to put the V Stem’s contribution further into perspective, an S5 with Cervélo’s last generation of aero bar with exposed cables adds 30g of drag. How so?

Well, in simple terms, it’s because air can flow through the V stem (not around as per regular set-ups) and through the rider’s legs.

Does it actually work? The proof is in the blisteringly fast pudding.

Easy speed

There are a number of things that make this bike quick besides the V bars: the main tube shapes, now larger in dimension with the relaxation of the UCI’s 3:1 ratio rule; the wheel cutouts; the external steerer; the narrow profile – and they all add up to a bike that is the personification of aero-rapidity.

I found myself cruising past riders who were clearly putting in considerable effort, and regularly bagged Strava medals on rides that weren’t exactly performed with intention.

Everything from the first crank stroke through to easily maintaining 41kmh on the flats felt effortlessly quick (usually I’d be happy with 38kmh).

The S5 also made light of headwinds, where I could almost feel – or at least imagine – the bike slicing the air with blade-like finesse.

However, the S5 does not enjoy blustery conditions, and nor does it thrive on technical roads.

To its credit the bike is relatively comfortable all told, and could be more so, as it will fit up to 30mm rubber, but it is found wanting in the cornering and handling departments.

Buy now from Sigma Sports here.

Compared to a more rounded race bike its handling sits in the early stages of languid, and although stable at speed (Cervélo has lowered the bottom bracket a touch to encourage stability) the S5 doesn’t duck and dive as I’d like or track the road anything more than ‘quite well’.

I think both of these things are unavoidable upshots of what Cervélo has set out to do, namely to provide greater stability by lengthening the trail (as a general rule, longer trail means more sedate handling) and to increase head tube and BB stiffness by 13% and 25% respectively.

That’s great for sprinters and those who live by smooth roads, but less great for tackling fast, bumpy corners.

For the rider I am and where I ride, I feel the S5 could do with a touch more frame flex to promote grip at the tyres, and shorter trail (the trail is 57mm incidentally, and I would call 53mm short).

That said, more assured cornering could be had on 28mm or 30mm tyres run at lower pressure than my chosen 85psi for these 25mm tyres.

So perhaps that’s a moot point. But what’s impossible to ignore is how the S5 handles in windy conditions.

Flicking the V

If the wind is relatively consistent then the S5 is great, but when the going gets gusty, the S5 gets pretty wavy.

It’s not an insurmountable problem – vigilance to conditions, such as looking out for gaps between buildings or hedgerows, pays dividends – and crosswind instability is a problem that befalls all aero bikes to some degree. It’s just in the S5’s case it is that much more pronounced.

However, in a strange way all this only makes me like the bike more, because there’s only one thing the S5 cares about: speed.

And it doesn’t mind who it upsets to get there. V Stem? More like a V-sign to anyone doubting how much fun a fast bike can be.

Buy now from Sigma Sports here.

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Cervélo launches new S5: disc brake only aero road bike

Cervélo redesigns its aero-road S-series for 2019; the bikes will be ridden by Team Sunweb

Words Sam Challis, 1st October 2018

Cervélo was the pioneer of the aero-road genre with its Soloist back in 2002, so in the development of the newly-launched S5 and S3 the brand had more than 16 years of experience to draw from.

The entire chassis of the new Cervelo S5 has visually moved on from its predecessor but the most striking change occurs at the front end.

A V-shaped twin stem flows back from an aero bar into an external fork that sits in front of and over the head tube.

The new design apparently makes the S5 42 grams of drag more efficient than the outgoing design, when measured with a rider.

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Image 14 of 23

While Cervélo claims this reduces drag by creating unimpeded airflow along the toptube, the primary motivation for the design was internal cable routing.

It means the cables can run more smoothly into the head tube, which thanks to the external fork design is hollow except for a threaded rod that pre-loads the headset, so the cables can pass through the centre of the headset bearings and on into the rest of the bike.

Despite its highly integrated appearance, the cockpit it fully adjustable with 30mm of stem height available, along with stem lengths from 90mm to 130mm and bar widths from 38cm to 44cm.

Even bar angle can be adjusted in increments of 2.5° via a sequence of shims.

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Image 15 of 23

Elsewhere there are the usual claimed improvements in stiffness and weight - a 56cm painted frame weighs 975g, and according to Cervélo the S5 is now 25% stiffer at the bottom bracket and 13% stiffer at the head tube, the latter largely thanks to the aforementioned new design.

The Cervelo S5’s geometry has been considerably adjusted too, being tweaked to share the latest Cervelo R5’s measurements.

In general the bike is longer and lower, thanks to feedback from the WorldTour pros that have used the old S5, while handling has been relaxed and the bottom bracket lowered to promote stability.

A new set of WorldTour riders look stand to gain from that feedback as it has been confirmed that Team Sunweb will ride the bikes for the 2019 season.

Four builds will be offered with prices ranging from £4,899 for Shimano Ultegra to £9,699 for Shimano Dura-Ace Di2. There will be a frameset-only option available too for £4,299.

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Image 5 of 23

Another little detail would be the S5 is now disc-brake only, as is the S3 for now. Rim-brakes will eventually be offered for the lower-spec bike but it is clear where Cervélo is placing its bike design priorities.

The S3 is slightly more conventional in appearance than its radical big brother but still features fully internal cabling and an updated frame design that Cervélo says saves 102g of drag over the previous S3.

Cervelo S5 review - 2016

Peter Stuart - February 2016

The updated Cervélo S5 is the hot favourite to be Cav’s weapon for 2016, but does it still lead the pack?

When Cervélo released the S5 four years ago it felt as if the brand had lifted bike design to new heights. Scientific white papers, wind-tunnel tests and stiffness analysis all played a part in a grand engineering project aimed at creating the most aerodynamic bike ever. In that sense it was a success, but it alarmed some onlookers with its abominable curves and aggressive tube shapes. This revision is undoubtedly more handsome, but Cervélo now has some formidable competition in the fight to lay claim to the fastest bike on the market.

Trek and Specialized have taken integration to the next level by hiding cables and brakes from the wind on the new Madone and Venge ViAS respectively, but with the S5 Cervélo has tried to keep things simple. 

‘We’ve always sought to make the bike fit standard components,’ says Phil Spearman, product manager at Cervélo. ‘We have a catchphrase: “Hide the brakes from the wind, not from the mechanic.”’ 

Anyone who has ever owned a bike with ‘hidden’ aerodynamic brakes will know that while concealing them does wonders to reduce drag, it’s a headache when it comes to replacing cables or making minor adjustments. Cervélo instead wanted a bike that was completely up to date but still fundamentally traditional.

The handlebar may be the best example of this juggling act. Yes, it looks a little like the skull of one of the alien invaders from Independence Day, but its design manages to be both aerodynamic and practical. 

‘One of the final frontiers for us in terms of aerodynamic gains was the handlebar,’ says Spearman. ‘Any time you have a round surface in the wind it costs you, and the drag on the handlebar is surprisingly huge.’ Compared to some other aero bars it looks strange, but it works happily with a standard stem so it’s more versatile than most one-piece aero cockpits, and its design also makes it more comfortable than some other aero bars when sprinting in the drops.

As for the rest of the frame, Cervélo had a tough time squeezing out any additional aero advantages compared to the previous version. While this new model claims to save an extra five watts of power at 40kmh, the true performance gains have been made through practicality rather than tube profiling. For instance the head tube is lower, meaning the rider will naturally adopt a lower, more aerodynamic position. The new bike will also accept 25mm tyres, which are considered to be faster than 23mm when paired with the right rims. This was a big gripe with the previous model, which was restricted to 23mm tyres. 

The cutting edge

The S5 is an elite class of superbike. Clip in and immediately it delivers an overwhelming sense of speed, responsiveness and rigid power delivery. It’s lighter and lower slung than its predecessor, so feels substantially more aggressive. It skims over the tarmac, leaving only a low rumbling noise behind.

Aerodynamics can be difficult to quantify in the real world, but a bike like the S5 really proves the merit of cutting drag from a frame. I could talk about my power numbers and average speeds, but the most visceral display of the aerodynamic wonders of the S5 came when I was riding into a blistering headwind. With gusts of 65kmh on a long solo ride, I remember looking down expecting to see 20kmh on my computer screen, but the S5 resiliently hovered at around the 30kmh mark. While I’m not suggesting the frame gifted me a whole extra 10kmh, it was clearly contributing some free speed. What’s more, the S5 feels every bit the race bike.

The previous S5 had a tall head tube that often invited mockery from committed racers, as it seemed at odds with the bike’s racy intentions. The reason for it was to improve aerodynamics, but it wasn’t always easy to dial in an aggressive fit to the bike’s geometry. The head tube was also less rigid than rival frames, exacerbated by the comparative stiffness of the bottom bracket, which sacrificed some of the handling precision. The front end is now unquestionably stiff, and the S5 has that pleasing sense of propulsion when throwing it from side to side as it hums up to speed unabated. The handling, equally, is accurate and well balanced – as long as it’s a calm day.

Aerodynamic frames and sidewinds do not mix well. The Cervélo S5 probably boasts the most dramatically flattened tube shapes on the market, so it’s no surprise that it suffers in a crosswind. During one 70kmh descent on an A-road, I rode past a gap in the hedgerow and found myself scrambling to stay in my lane as the bike was blown across the road. Only part of that is down to the frame. After switching the wheels to a set of Bontrager Aeolus 5s (slightly shallower at 50mm and with a more rounded profile) stability was significantly increased. 

My mother asked me why I was taking a hammer to a £7,000 bike.

The only other flaw I found with the S5 was with the steerer insert, the anchor point for the top cap bolt that’s used to pre-load the headset. In modern bikes we might expect an expander bung to press directly into place within the steerer tube, but Cervélo uses an aluminium insert that’s glued into place. While that shouldn’t be a problem, the insert on this bike drifted out of place and proved difficult to reposition. 

Bashing it back into place during a visit to my family over Christmas, my mother asked me why I was taking a hammer to a £7,000 bike. I really had no good answer. Eventually I managed to fix the problem with the right tools and some epoxy, but this kind of thing really shouldn’t happen with a bike of this calibre.

Pro favourite

Those issues aside, the Cervélo S5 really is every bit the superbike, as revealed by the enthusiasm of the pro teams that ride them. The MTN Qhubeka pro team had the choice between a lightweight endurance frame (R5) and a more hefty aerodynamic one (S5), and riders such as Tyler Farrar, Edvald Boasson Hagen and Steve Cummings have stuck religiously to the S5 in all situations. In 2015 the new S5 was even their choice for the cobbles of the Tour of Flanders, something we would never have seen with the last iteration.  

A big part of the increased enthusiasm for the bike is a step forward in comfort, which is largely thanks to the tyres. The switch to 25mm has transformed the feel of the bike. Combined with the more decisive handling and lower-slung position, the new S5 has gone from an exercise in scientific precision to a fully rounded race bike. I also enjoyed climbing on it, as its stiff response had me edging my power up bit by bit. At a little over 1kg for the frame, it’s certainly no heavyweight either.

Cervélo has taken a different tack to its rivals. While Trek, Specialized and Scott have been busy in the wind-tunnel trying to find more aero gains, Cervélo has taken a bike that was already the epitome of aero and made it a better all-round ride.

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