Specialized Roubaix SL8 Comp review | Endurance Bike of the Year contender

The Future-Shock equipped Roubaix has been with us since 2017, and it’s the 20mm of suspension up front that sets the latest Roubaix SL8 apart from much of the endurance bike competition.

Now in its third incarnation, the Roubaix SL8 blends refined ride quality with aerodynamics for a sporting but smooth ride.

That said, value for money is a real sticking point here, with mediocre wheels holding the Roubaix SL8 Comp back from scoring higher marks.

Specialized Roubaix SL8 Comp frameset details

At the heart of the Roubaix SL8’s design is the Future Shock suspension system, which offers up to 20mm of movement.

This design differs from the accepted suspension types usually found on bikes – splay (where the fork moves fore-and-aft to absorb bumps and vibrations) and axial (up and down movement from a suspension fork).

The Future Shock’s position above the head tube and below the stem is all about suspending the rider rather than the whole bike. Specialized says the intention is to enable the bike to move underneath you, absorbing the impacts, while isolating you from the fatiguing vibrations.

The Future Shock unit is made up of a fluid-damping cartridge, which is attached to a spring.

On this Comp-level model, the damper is fixed in its softest setting (the S-Works and Pro bikes feature a damper adjuster in place of the top cap) – Specialized calls this Future Shock 3.2.

The bike comes with three different springs and five preload rings so you can still tune the behaviour of the unit to suit your needs.

What about the rest of the frame?

Specialized claims the Roubaix SL8 brings some marginal improvements in aerodynamics – a rider putting out 3 watts/kg over a 100km ride would end up finishing 11 seconds faster than before (or be 17 seconds quicker covering 100 miles).

At the rear, there's another shock-absorbing design, which is a development from the 2017 Roubaix.

Incorporating the Roubaix SL8’s renewed attention to aerodynamics seen throughout the frame, the original’s skinny, round and elastomer-infused head has been replaced by a deep aerofoil shape.

It features a low-down clamp system, where the post is fixed in place by a wedge deep down inside the seat tube.

Specialized says this allows for far more of the seatpost to be ‘exposed’ above the clamp. Because the seat tube above the clamp is larger than the post diameter, it’s said to be able to move up to 18mm fore and aft, boosting compliance.

This added complexity would normally trigger warning signals around excess weight, although at a claimed 950g (in a size 56cm) for this Fact 10r carbon frame, it isn’t heavy.

The frame and fork are now designed to accommodate tyres up to 40mm, which is huge for a road bike.

This influences the front centre of the bike, elongating out by 10mm over the previous Roubaix. The wheelbase of 1,031mm for a 58cm bike is (as you’d expect) up by 20mm from the older model's 1,011mm.

That increase in tyre clearance, along with the addition of a third set of bottle bosses under the down tube and bento box bosses on the top tube, is telling. It positions the Roubaix SL8 Comp firmly in the all-road camp, and certainly makes it gravel-capable.

That could be considered at odds with the aerodynamic makeover, although I’m very glad to see Specialized has kept the full mudguard bosses.

This is something both Canyon and Cinelli have omitted from their similarly ‘aero-optimised’ endurance bikes, but Giant has kept with the Defy.

Specialized Roubaix SL8 Comp geometry

Despite the changes to the front-centre and wheelbase, Specialized hasn’t messed with the Roubaix’s ride position and steering geometry.

The tall stack of 630mm on my 58cm test bike and 397mm reach are combined with a race-ready 73-degree head angle and a trail of 57mm, which adds plenty of snap to the steering.

Compared to the racy Giant Defy, it’s 34mm taller in stack, but 4mm longer in reach in a size XL.

The similarly sporty Canyon Endurace (in a size L) is 19mm lower and 10mm shorter than the Specialized Roubaix.

Specialized Roubaix SL8 Comp specifications

This Comp-level Roubaix SL8 is well equipped, sitting beneath the S-Works and Pro models.

Specialized own-brand parts are a real plus, from the slick proprietary carbon Pave seatpost through to the Power Sport saddle, which I find particularly comfortable and well-suited to the rigours of long-distance riding. It’s one of the original short-nosed saddle designs.

Up front, the alloy Hover bar with its compact drop and reach, and (most importantly) slight rise from the stem, is one of the most ergonomically pleasing road bike handlebars I’ve used.

It’s wrapped in quality Supacaz Super Sticky Kush tape, so no expense has been spared here.

The biggest highlight of the Comp is certainly the Shimano 105 Di2 R7100 groupset – its slick and smooth operation is every inch a match for the bike’s smooth-riding nature.

The 50/34-tooth chainset and 11-36t cassette are both classic endurance bike choices, bringing lots of range, and low gearing for big climbs.

Shimano's 105 hydraulic brakes are excellent and live up to the shifting performance with plenty of power and a confidence-inspiring feel. However, as I found on the similarly equipped Cinelli Pressure ADR, the rotors did exhibit a little noise once they were wet.

Its rolling stock combines tubeless-ready DT Swiss G540 alloy rims with a big-tyre friendly 24mm internal width, laced via 24 spokes onto Specialized hubs. It's unflashy, but it makes for a solid-quality wheelset.

DT Swiss describes the G540 as a gravel rim. The 28mm-wide (external), 25mm-deep rim is designed for tyres up to 53 wide (although, of course, you’re limited to the Roubaix frameset’s 40mm tyre clearance).

The Specialized hubs are of decent quality, featuring easily replaceable cartridge bearings, but it all adds up to a wheelset that’s close to 2kg in weight.

Similar aftermarket road bike wheels, such as DT’s G540 with DT 350 hubs, retail for £200. I’d argue £200 wheels on a £5,000 bike don’t exactly scream value for money, no matter how competent they are.

The Specialized Mondo 700x32c tyres are tubeless-ready, but come set up with inner tubes from point of purchase.

The £500 cheaper Lauf Ùthald (with an otherwise comparable spec) gets Zipp’s impressive 303S carbon wheels, which at 1,558g and just over £1,000 aftermarket, are leagues ahead of the Roubaix’s alloy hoops.

Canyon’s Endurace CF SLX 8 Di2 gets similarly impressive wheels – DT Swiss’ ERC 1400 Dicut 35s. They weigh a claimed 1,477g and come with an aftermarket price tag of over £1,000.

Specialized Roubaix SL8 Comp ride impressions

For poorly maintained tarmac and single-lane back roads strewn with mud, gravel, and winter wear, the Roubaix SL8 is probably the best bike on sale right now.

The way in which the front end smothers vibrations and nulls hits from potholes and changes in surface textures is brilliant.

That said, it exhibits something of a split personality – compared to the previous incarnations (and especially the original 2017 version), the back end of the SL8 is certainly firmer.

While not uncomfortable (the wide tyres do some vital work here), the relative softness felt through the front is a stark contrast to the rigidness felt through the back.

I’d expect a bike with this much compliance and comfort built in, overall, to lack in other areas (such as speed), but the Roubaix covers ground quickly and efficiently.

This is notably impressive to me, because the Roubaix’s Future-Shock filled front end means it can’t perform the typical aero trick adopted by the likes of the Canyon Endurace, Giant Defy and Cinelli Pressure ADR of hiding the brake hoses in the head tube.

Usually, this is considered a sure-fire trick in reducing drag easily (although Lauf, as shown by its Ùthald bike, would disagree).

I can’t vouch for the watt-saving claims, but the Roubaix was easily as quick over rolling terrain as the Canyon, Cinelli and Giant – and certainly felt more sprightly than the Lauf.

On longer climbs, the Comp feels capable, though not outwardly quick. It’s really a bike for sitting in and concentrating on spinning the cranks, rather than getting out of the saddle and attacking.

The wheels, while tough and shaping the impressive tyres well, feel weighty, take the edge off the Roubaix’s impeccable handling manners and hold it back when the road turns upwards.

When it comes to coming down the other side, however, the Roubaix has monstrous talents. The compliance of the front end and the big-volume, textured-tread tyres combine to provide confident grip that’s hard to match.

The SL8’s ability to hold its line, even when the road surface suggests otherwise, is somewhat addictive. On my multiple test rides, I found myself riding up more climbs than I normally would just so I could enjoy the bike’s descending prowess.

Specialized Roubaix SL8 Comp bottom line

The Specialized Roubaix SL8 Comp has a huge amount going for it. It conquers cruddy surfaces like nothing else and that makes it one of the very best endurance bikes for poor roads.

The drivetrain and braking are both at the top of their game too, and I’ve no complaints with any of the contact points.

In contrast, the wheelset, while competent, doesn’t sparkle like the rest of the bike and wouldn’t be out of place on a bike half the price of the Roubaix Comp.

So, in conclusion, the SL8 Comp is a brilliant endurance bike. It's fast and very forgiving, but in no way is it frugal on the wallet.