Specialized Roubaix SL8 Sport 105

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The Specialized Roubaix SL8 Sport is the latest incarnation of Specialized’s long-standing and successful Roubaix endurance bike.

The present range features Future Shock suspension hidden under the stem, a compact frame, a carbon seatpost and dropped seatstays for comfort, as well as some aerodynamic benefits.

Specialized has also boosted tyre clearance to 40mm, putting it firmly into all-road and light gravel riding territory.

In fact, Specialized’s overworked marketing team claims the Roubaix SL8 is ‘lighter, faster and smoother’ than any road bike ever made.

The Roubaix SL8 Sport’s ride is certainly impressively smooth over surfaces ranging from rough country lanes to rutted grit and gravel, without sacrificing speed.

Specialized Roubaix SL8 Sport 105 frame details

There aren’t too many surprises when it comes to the Roubaix’s frame and fork – a full-carbon pairing made in Taiwan.

Fans of threaded bottom brackets will be pleased to see that standard here, and there are a few features that demonstrate the bike's all-road or even gravel-adjacent riding ambitions.

The Roubaix’s tyre clearance has gone up significantly compared to the previous generation, from 33mm to 40mm, which offers a massive range of road tyres from which you can choose.

Specialized says it has shaved 50g from the frame, so it now tips the scales at only 825g (claimed, in a size 56cm).

For an all-roader with light gravel-riding ambitions, it remains impressive, even if the overall 9kg weight isn’t that light.

While neither the frame nor fork have fittings for racks (which some, understandably, will see as an oversight), you get more than the usual number of bosses on the frame.

In addition to the usual inner-triangle bottle bosses, there’s also a pair underneath the down tube, while the top tube gets ‘bento box’ mounts.

But it’s the bike’s comfort that Specialized emphasises, and just above the head tube sits the discreet Future Shock unit. Here, it’s the basic ‘3.1’ version, with an undamped spring providing the 20mm of travel.

The frame leaves a fair amount of the seatpost exposed to further boost comfort, but what isn’t so evident is the Roubaix’s ‘Dropped Clamp’. This in fact clamps the seatpost 65mm down into the seat tube, which enables the post to flex further still. Specialized refers to this design as ‘AfterShock technology’.

Less important to me, Specialized’s designers have also made the frame and fork more aerodynamic by changing the shape of the fork and dropping the seatstays lower, which is claimed to help hide them from the wind.

My colleague Ashley Quinlan rated the Roubaix’s speed highly when he rode the S-Works Roubaix SL8 at launch.

Specialized Roubaix SL8 Sport 105 geometry

The Roubaix’s endurance geometry is pretty similar to that of the Basso Venta R and Merida Scultura Endurance 4000 I've also tested – just a little bit more relaxed than either.

It has the longest wheelbase of the test trio, at 4mm longer than the Merida in an equivalent size 54cm, although at 1,005mm it’s 27mm longer than Specialized’s Tarmac race bike.

Interestingly, at 122mm, the Roubaix has a much shorter head tube on paper, not only than the other two bikes it’s up against, but also the Tarmac’s 137mm.

However, these disparities are eased out by the space the Future Shock takes up in the stem and the height added by the rise of the Roubaix’s handlebar.

As a result, the Roubaix has the highest stack figure of the three test machines, although the stack is only 5.5mm greater than the Basso and 1mm more than the Merida.

The 72.3-degree head angle doesn’t lead me to expect lazy handling.

Specialized Roubaix SL8 Sport 105 specification

As the name suggests, the Roubaix SL8 Sport 105 gets a full raft of 12-speed hydraulic Shimano 105 R7100 components.

The Roubaix gets the familiar 50/34 compact chainset but goes even further than the Basso and Merida in speccing the widest 11-36t 105-level cassette. Every little helps when things get steep, so this gets a thumbs up from me, and should appeal to those who want to make climbs as easy as possible.

The result is a sub 1:1 ratio bottom gear, and a gear range of around 26-124in, which should cover most of us for most situations.

And with 12 ratios there are still no huge gaps between gears, with one-tooth jumps for the first five gears and four-tooth jumps only for the last three shifts. Shifting was smooth and accurate across the range.

Braking is powerful and controlled, with great modulation – and requiring very little effort.

But as good as Shimano 105 is, it's not the highlight of the Roubaix spec – that title belongs to the Future Shock suspension stem.

It’s not obvious when you first look at the bike, because unlike mountain bike suspension or the RockShox fork that shocked Paris-Roubaix in the early 1990s, it’s hidden in the stem.

The system offers 20mm of “smooth, stiction-free travel between the stem and head tube” according to Specialized. It’s not wrong – it really works.

The suspension consists of a spring that absorbs impacts and up to five preload washers, which influence the compression rate. You can choose from firm, medium and soft springs (which are all supplied).

For those worried about wear, Specialized says the latest incarnation is also the toughest and most resistant to the elements, thanks to the use of a thicker boot and a greater number of seals.

This front suspension is paired with Specialized’s Pavé carbon seatpost, named after Paris-Roubaix's famous cobbles. The dropped clamp is designed to ensure there’s a lot of exposed seatpost for additional compliance.

I was a bit surprised that the Pavé has a D-profile, resembling a skinnier version of Giant’s D-Fuse post. Specialized describes it as the first seatpost that’s “[both] compliant and aerodynamic”.

The Pavé post is topped by Specialized’s short-length Power saddle, which I got on with very well (albeit, of course, saddle fit is subjective).

The comfort theme is finished off with Supacaz’s excellent Super Sticky Kush bar tape wrapped around a bar that has slightly flattened, wing-profile tops – said to be for additional comfort, rather than any potential aero benefit.

The riser bar adds another 25mm to the height at the front, which may not appeal to all, but helps to relax the riding position a little (and complement the components immediately beneath it).

The wheels are the same as on the Roubaix SL8 Comp that Warren reviewed.

He found the wheelset, pairing DT Swiss GT540 alloy rims and Specialized hubs, solid and unflashy, but he felt what is essentially a £200 wheelset was out of place on a five-grand bike.

On this cheaper bike, they’re a sounder choice, but still ripe for a later upgrade.

The tyres are 32mm S-Works Mondo 2BRs, which are tubeless-compatible and impressive to see at this price point, where other brands might spec middling tyres.