2023 Cervélo S5 Force eTap AXS review

The Cervélo S5 has often pushed the boundaries of aero road bike design, bringing features previously confined to time trial bikes across to a platform optimised for bunch racing.

The original S5, launched in 2011, took heavy inspiration from the Cervélo P4. It’s no surprise, then, to see echoes of the Cervélo P5 in the latest S5.

Visually, the latest S5 is only subtly different from the outgoing model, which was launched in 2018 with its unorthodox V stem and hinge fork.

There have, though, been a few key changes, some of which have the potential to make a significant difference to your day-to-day riding.

While it’s not a light bike by any measure, it won’t surprise many to discover a bike with such heavily sculpted tubes feels incredibly fast on favourable terrain.

The simplified front end and added tyre clearance of this latest version also make the S5 a bike that’s slightly easier to live with than its predecessor, and it’s all the better for it.

Small changes, big performance

Considering its outward similarity to the previous model, we might have expected the new S5 to have a fairly quiet launch.

Piloted intermittently by the Jumbo-Visma team at the 2022 Tour de France, however, it instead played its part in one of the most dominant team performances of the modern era.

You could argue the riders might have performed in a similar manner on any, but still, having a good one doesn’t hurt.

Changes to the S5's frameset come mainly in the form of small tweaks to the tube shapes and sizes.

These account for the latest updates to the UCI’s technical regulations, which allow for slightly deeper, more aerodynamic tubes than previously.

Cervélo has, for example, extended the nose of the bike above the front wheel, which increases the effective size of the aerofoil at the front end. It also comes to an even narrower point on its leading edge.

The Cannondale SystemSix has a similar feature on its head tube, although it uses a conventional steerer arrangement.

Beyond that, the other major change comes in the form of an extra 6mm of tyre clearance. The new S5 can accommodate tyres up to 34mm (measured width), compared to the 28mm clearance on the outgoing mode. This puts the new S5 in territory that was considered gravel-friendly not too long ago.

Do you really need that type of clearance on an aero road bike, though?

The answer is probably ‘it depends where you ride’, but the inclusion of a set of ultra-wide Reserve 52/63 aero wheels (more on these later) and 28-622 tyres, which plump up to over 31.5mm when inflated, suggests the new face of speed might not be solely about having the smallest frontal area possible.

Cervélo S5 Force eTap AXS geometry and ride feel

Because of its heritage and futuristic looks, I expected the new S5 to be fast, and it doesn’t disappoint in that regard. However, I didn’t expect the ride quality to be so smooth.

I have 28-622 tyres on every road bike except my time trial bike (which is old and only has clearance for 25mm tyres), these days. So when I see those mounted on a bike, I typically know what I’m going to get.

Here, though, you’re getting an effective tyre width of over 31.5mm. The Vittoria Corsa TLR G2.0 tyres on my test bike measured 31.7mm when inflated to 60psi on the Reserve rims, with seemingly no aero penalty at all, because the whole package is optimised for this.

As always, you have to get your tyre pressures right to take full advantage of it, but when you do the ride quality is thoroughly impressive for a bike with no specific comfort-improving features (such as the Trek Madone SLR’s IsoFlow system).

In conjunction with its excellent, sharp handling, the new S5 feels exceptionally planted and predictable at speed. It glides over road imperfections that similarly stiff bikes with narrower tyres might normally punish you for.

Even with the brakes set up euro-style (front brake, left / rear, right – the reverse of what I typically ride), I had great fun riding sinuous descents such as Cheddar Gorge.

Of course, the frameset itself is no memory foam mattress – when you get up out of the saddle and stamp on the pedals, you still get the typical snappy response you expect of a WorldTour-level race bike.

But that responsiveness doesn’t come with an obvious comfort penalty, as it so often does with pure race bikes.

It certainly doesn’t feel heavy, but the scales also don’t lie – at 8.2kg for a size 56cm bike without pedals or bottle cages, it’s almost 800g heavier than an equivalently specced Cervélo R5.

The S5 is, without a doubt, likely to be the faster bike away from the steepest, longest climbs, but this isn’t a bike built to appease weight weenies or hill climb racers.

While there are lighter aero bikes, such as the Canyon Aeroad CFR, an aero road bike around the 8kg mark isn’t unusual compared to competitors, such as the Trek Madone SLR, Cannondale SystemSix and Orbea Orca Aero.

It would be possible to build a lighter S5, with an even more expensive build spec and wheels with shallower, narrower rims.

Whether that would be a smart use of money on a bike such as this is questionable, though.

Cervélo S5 Force eTap AXS finishing kit

As is typical of fully integrated aero road bikes, the finishing kit on the Cervélo S5 is mostly proprietary.

The seatpost is identical to that of the outgoing model, with the exception of a smaller, 15mm offset (the bike used to ship with a 25mm-offset seatpost as standard).

While saddle position and bike fit are personal things, the move to a more inline seatpost generally makes sense on an aero road bike, because it puts you further forward over the bottom bracket. This provides a more open hip angle when riding in an aggressive position.

If you prefer a different amount of setback, though, the old 25mm and 0mm setback posts are still compatible with the new S5, so there’s plenty of choice.

That’s handy, too, because the wide-set saddle rail clamps don’t give you much room to adjust the saddle position fore or aft.

If you’re sticking to the limits marked on the rails of the stock Selle Italia Novus Boost Evo SuperFlow Ti saddle (which is very comfortable, even if you might reasonably expect carbon rails at this price point), you’ve only got a centimetre or so of adjustment range available.

However, given the availability of three different seatposts with varying offsets, it’s unlikely to be a deal breaker.

But it’s annoying you might have to shell out for a replacement seatpost, rather than being able to optimise your saddle position by simply sliding it forward or back on the rails a few centimetres, as you can with the vast majority of other seatposts.

Simplified front end

Cervélo has simplified the front end, making fit adjustments easier than before, and shaving off a fairly insignificant 53g of weight.

While you’ll still need to disconnect the hydraulic disc brake hoses to swap out the stem, there are no longer stack-specific bolts or myriad small parts required.

Testing the waters, I asked our overworked workshop manager, Will Poole, to remove a few headset spacers before I took the S5 home.

To his, and the bike’s, credit, he didn’t laugh me out of the workshop and tell me to “come back in a week”. Instead, the job was done on the same afternoon and, judging by Will’s demeanour when I returned to collect the bike, with minimal stress.

Despite appearances, the hydraulic hoses route externally on the new handlebar, in a small channel underneath the handlebar tape. This means you should be able to swap to a different bar width without disconnecting the hoses.

It’s also possible to rotate the bar by 5 degrees, with no discrete steps or wedges required (as there were previously).

The V stem is available in sizes from 80mm to 130mm (in 10mm increments), and the handlebar in widths from 380mm to 440mm (in 20mm increments).

If this were my bike, I’d lament the lack of a 360mm handlebar-width option, but that’s a niche concern.

Looking more broadly, a flared handlebar, with narrower hoods and slightly wider drops, might have also helped Cervélo pick some low-hanging aero fruit.

Narrow handlebars can be an easy aero win, and flared bars – as seen on the latest Trek Madone SLR – arguably offer the best of both worlds, with a narrow position on the hoods for high-speed cruising, and a wider drops position for greater leverage and control during sprints and high-speed descents.

Cervélo S5 Force eTap AXS groupset, wheels and tyres

SRAM Force eTap AXS groupset

There’s little to say about SRAM’s excellent Force eTap AXS groupset that hasn’t already been said.

It provides performance comparable to SRAM’s flagship wireless electronic groupset, Red eTap AXS, in a slightly heavier but significantly cheaper package.

As I've experienced before with SRAM hydraulic disc brakes, there was a hint of brake rub when standing up out of the saddle and yanking on the bars, but it isn’t a major issue – braking performance is otherwise excellent.

The SRAM Force power meter is a great inclusion. It uses the same internals as the excellent Quarq DFour DUB power meter, and should provide similarly accurate and reliable data.

Reserve 52/63 wheelset and Vittoria tyres

The Cervélo S5 is built around a new set of aero wheels from house brand, Reserve.

The Reserve 52/63 wheelset is, according to Cervélo, key to the new S5’s improved performance.

While the bike as a whole is said to be around 8 watts more aerodynamic (at 48kph / 30mph), the Reserve 52/63 wheelset is claimed to “save a little over 5 watts” compared to Reserve’s outgoing 50/65 wheelset.

It uses a set of hooked carbon rims with radically wide external dimensions, with a 35mm-wide / 52mm-deep front rim and a 34mm-wide / 63mm-deep rear rim, built around Zipp ZR1 ST hubs.

Unlike Hunt’s similarly broad Limitless aero wheels, which use a patented carbon fibre and co-moulded polymer rim construction, the Reserve rims are fully carbon and have super-wide internal widths as well (25mm and 24mm, front and rear, compared to 21mm on the Hunt wheels).

This, as already mentioned, plumps the 28-622 tyres up to 31.7mm wide when inflated to 60psi / 4.1 BAR.

Even by today’s standards, that’s unusually wide for an aero road bike.

It’s undeniably effective, though, at least around the rough backroads of south west England.

It feels as if you’re having your cake and eating it, because you appear to get the aero benefits of the deep-section wheels without a drag penalty from the wider tyres.

The Vittoria Corsa TLR G2.0 tyres are also some of the most supple road tubeless tyres around, and though they’re fairly delicate, they offer a great balance of speed, grip and comfort.

Cervélo S5 Force eTap AXS bottom line

The new Cervélo S5 is fast, comfortable, simpler to adjust and offers great handling.

Nitpicks and the saddle-clamp issue aside, the only notable downsides are that it’s at the weightier end of things and – when compared to similarly specced competitors – undeniably expensive.

Even in an age of across-the-board price rises, £9,599 for a build with this spec puts it at the top end of the scale, alongside bikes such as the Trek Madone SLR 7 eTap.

There are top-performing competitors that can offer a similar package for less money (such as the Merida Reacto, Canyon Aeroad, Orbea Orca Aero and Cannondale SystemSix Hi-Mod).

However, value is also a highly personal thing, and Cervélo would doubtless argue the S5’s stellar performance and pedigree at the highest level justifies its price.

Overall, if you can stomach the price of entry, the new S5 is a fantastically fast and fun bike to ride.