Specialized Roubaix SL8 Expert review – a superbike for all seasons

In 2024 the Specialized Roubaix will be 20 years old – and what a journey it’s been. A ‘Hell’ of a journey you might say. The Roubaix has won seven editions of its namesake Monument Classic, most recently with Philippe Gilbert in 2019.
The Roubaix SL8, launched earlier this year, has come a long way since 2004. Back then Specialized’s endurance bike – the first of its kind with a higher stack and smooth-riding carbon frame – offered an alternative to the steep, aggressive, harsh race bikes of the era.

But 20 years on, race bikes are much more comfortable. So comfortable in fact that the same aero bike can be ridden at either Milan-Sanremo or Paris-Roubaix with just a change of tyres. So where does that leave the Specialized Roubaix?
The latest iteration has evolved far beyond its original remit. According to Specialized, riders are asking more from their bikes than ever before, and the Roubaix SL8 answers that call: “Lighter, faster, and smoother than any road bike ever made, unleashing unmatched confidence.” It’s still an endurance road machine, but it’s not afraid of a little gravel, says the US brand.

So what’s new? There’s an improved Future Shock suspension system at the front, After Shock suspension at the rear and huge tyre clearance for 40mm rubber. At the same time it’s lighter and faster: an optimised carbon layup is claimed to shave 50g off the weight of the top S-Works frame compared with the 2020 model while improved aerodynamics make it a claimed four watts faster than before.
Mudguard eyes have been added plus mounting points for a top tube pack and an extra bottle cage.

Check out our launch story for all the details and the specs, but here we’re looking at the SRAM Rival AXS-equipped Roubaix Expert – £6,000 at the time of writing and the third in the range behind the S-Works and the Pro – that I’ve been riding for the past month.

Frame and fork

The flagship S-Works Roubaix SL8 is made from Specialized’s premium 12r carbon and weighs a claimed 825g (total 7.3kg weight for a size 56 S-Works Roubaix). All other models, including the Expert here, are made from 10r carbon and as such are a little heavier for the same level of stiffness.

The silhouette of the Roubaix SL8 is not hugely different from that of the 2020 version, but Specialized has saved those four watts (equivalent to 17.7 seconds over 100 miles riding at 3W/kg – not much, but the brand says the old Roubaix was already class-leading in its aerodynamics) by creating a new fork with deeper blades, a reshaped head tube and down tube and lower seatstays that are more hidden from the airflow.

It would be an easy win to save yet more watts by hiding cables from the airflow, but because the Future Shock suspension, sited below the stem, supplies 20mm of travel, this isn’t possible. The brake hoses need to be able to bend as the bar moves up and down in its travel. It’s not such a clean look compared with rival endurance bikes such as the Canyon Endurace, but unavoidable in this case.
The new Roubaix’s tyre clearance has gone up from 33mm to 40mm. The Canyon Endurace has space for maximum 35mm, so Specialized wins here. The Roubaix now has mudguard mounts (the Canyon still doesn’t) and can fit 35mm tyres with mudguards.

The geometry and sizing is based on the previous Roubaix with 10mm added to the front-centre for the bigger tyres.

The size 56 I tested has a stack of 605mm and a reach of 389mm, so it’s pretty tall at the front, with no possibility of slamming the stem since the Future Shock – which adds 30mm of stack – sits underneath the Hover bar, which itself has a 15mm of rise compared with drop bar with a standard flat top.

Suspension

The suspension deserves its own section since it’s what the Roubaix SL8 is all about. The bike’s strapline is ‘smoother is faster’ and this is achieved, according to Specialized, by suspending the rider not the bike: the travel is directly underneath the rider’s contact points at the bar and saddle.

Future Shock at the front is faster because it moves up and down to absorb shock instead of deflecting backwards on impact as a traditional fork does, according to Specialized.

The Expert has Future Shock 3.2, which doesn’t have the adjuster dial on the stem top cap of the 3.3 (fitted to the S-Works and Pro models) but it’s possible to swap out the spring inside the damper for a softer or harder ride and there’s a manual with instructions – though I didn’t, because the medium spring it comes with felt right, and Specialized’s chart recommends the medium one for my rider weight anyway. The softer and firmer springs are included with the bike.

At the rear is After Shock – a D-profled carbon seatpost with a dropped clamp that’s 65mm down inside the seat tube allowing more rearward deflection since it’s a longer lever. Above the clamp, the seatpost is effectively floating inside the larger seat tube, sealed by a rubber boot at the junction with the top tube (under which the long clamp bolt is also located). This avoids the wear issues that afflicted the Canyon Aeroad in 2021, which also used a seat tube with a lowered clamp, but Canyon’s VCLS carbon seatpost, as used by the Endurace, uses a leaf spring construction with a clamp in the standard position to achieve the same 20mm of deflection.

Specialized says the Roubaix SL8 supplies the maximum rearward deflection possible without needing a damper, the solution for its Diverge STR gravel bike.

Components

The £6,000 Roubaix SL8 Expert is specced with a SRAM Rival AXS groupset with a power meter chainset. The wheels are Roval Terra C – carbon with a 33mm depth and wide 25mm internal rim width with S-Works Mondo 32mm tubeless-ready tyres. These are all good-quality components but at this point it’s worth checking what the Roubaix SL8’s competitors offer.

The Canyon Endurace undercuts it quite significantly: £750 less at the time of writing, the Endurace CF SLX 8 AXS Aero has a SRAM Force groupset with a power meter chainset and superior deep-section DT Swiss ERC 1400 Dicut wheels.
The Vitus Venon EVO-RS Aero gets a SRAM Force groupset (though no power meter and it has alloy wheels) for £1,600 less.

The Trek Domane SL6 AXS Gen 4 with Rival AXS (also no power meter and it has alloy wheels) is slightly more expensive than the Vitus but still over £1,000 below the Roubaix SL8 Expert and the Giant Defy Advanced 0 with Rival AXS is almost half the price of the Roubaix SL8 Expert - though again comes without a power meter and has alloy wheels.

So judging by the spec, the Roubaix SL8 Expert is priced high for a Rival AXS bike, but things even out at the top end: the flagship S-Works model with SRAM Red at £12,000 is no more expensive than its top-spec competitors.

Ride impressions

I’m going to cut straight to the chase and say the Roubaix SL8 is the most comfortable road bike I’ve ever ridden. I’m a big fan of Canyon’s VCLS seatpost but at the front end the Endurace relies on tyre squidge like any other bike, whereas the Roubaix SL8 with the After Shock seatpost and Future Shock front – and big S-Works Mondo 32mm tyres – feels plusher overall.

That said, the execution is subtler than you’d think from the marketing. At first I didn’t believe the front Future Shock was even being activated, especially as there’s no sag setting and it was at the top of its travel, but on rougher surfaces I could see the brake cables moving, telling me that the bar was moving up and down.

At higher speeds, especially descents, the bike benefits from the suspension that much more. Going fast downhill it feels like a motorcycle. Very stable, very smooth and loads of fun. Generally the faster you’re going, the better it works.

Uphill out of the saddle, I expected the Future Shock to bob, but since it’s laterally solid a standard climbing style, which exerts more of a sideways twisting force on the hoods, doesn’t activate it.

The more I rode the Roubaix the more I enjoyed it.

Downsides? Future Shock inevitably adds a bit of weight, and the Roubaix SL8 Expert at 8.7kg is not light. And there’s no way around the tall front: it’s not possible to slam the stem if you want a lower stack height.

Comparing the fit of the Roubaix SL8 to my ideal bike fit measurements by fitter Giuseppe Giannechini, on the Roubaix I’m almost 5cm higher at the front – that’s before adding in the 1.5cm rise of the Hover bar – and around 4cm shorter. As with most endurance bikes, it’s important to be sure that the geometry is right for you. Personally I prefer rider weight to be a little more evenly distributed between saddle and bars, even for the long rides that endurance bikes are aimed at.

However, it’s still possible to tuck into an aero-hoods position that’s not too far off optimal, and I rode my usual 25-mile loop only a little slower than I’d do for a similar power on a race bike. Also bear in mind it was November and December when I tested the Roubaix, which means cold tyres/higher rolling resistance and higher air density.

But thanks to its smoothness, the Roubaix is deceptively fast even in winter. Freewheeling on a slight downhill next to a rider of a similar weight on a ‘standard’ bike with 28mm tyres and no suspension, I was dropping him.

To his further disgust, I flicked mud into his face as I pulled in front. I didn’t fit mudguards even though I rode the Roubaix SL8 through some horrible weather. But if you did, you could ride it all year round without upsetting your companions and even use it as an upmarket commuter too.

Verdict

It’s tempting to dismiss the latest latest Roubaix as neither fish nor fowl, particularly now that it’s no longer the number-one race bike of Specialized’s pro teams at the cobbled Classics and it’s not a full-on gravel bike like the Diverge STR either. But it is incredibly versatile and ticks a huge number of boxes, arguably more than any other road bike out there today, with very little compromise at either end of the spectrum.

Its biggest USP is its smoothness. It might not be the queen of Classics any more but it's the undisputed king of comfort.