Specialized unveils Roubaix SL8, the "fastest, lightest and smoothest endurance road bike ever made"

The new Specialized Roubaix SL8 has broken cover, with the lofty claim that it’s the “fastest, lightest and smoothest [endurance] road bike ever made”.

The brand says the redesigned Future Shock suspension system, new AfterShock seatpost design and 40mm tyre clearance combine to make the Roubaix SL8 53 per cent more compliant than its nearest competitor.

Aerodynamics have also been addressed, with modified tube shapes producing a claimed four-watt saving (at an unspecified speed) compared to its predecessor, while a 56cm frame is said to weigh 828g in a size 56cm (50g less).

The Specialized Roubaix SL8 is available in seven iterations – a headlining S-Works version with the brand’s top-spec 12r carbon layup, and six 10r carbon models.

Prices top out at £12,000/$14,000/€14,000/AU$19,900. The cheapest full-build model is priced at £2,500/$2,800/€2,800/AU$3,900, while an S-Works frameset costs £4,750/$5,500/€5,000/AU$8,900.

How does it ride? You can read our first ride review of the Specialized S-Works Roubaix SL8.

The smoothest road bike ever made?

The Specialized Roubaix SL8 features a remodelled Future Shock damper in the head tube, a new ‘AfterShock’ seatpost design, and 40mm (measured width) tyre clearance.

Specialized claims these developments – plus the fine-tuning of the frame’s carbon layup – help the Roubaix cut the harshness of impacts felt at the handlebars by 53 per cent compared to its nearest tested competitor, the Cannondale Synapse.

Specialized’s testing involved telemetry data gathered from a static rig applied with weights, and through the use of accelerometers and string potentiometers to measure the impact of a series of 22mm-tall bumps through the bars and saddle.

The Trek Domane and previous-generation Canyon Endurace were also tested using Specialized’s own protocol, with both performing slightly worse than the Cannondale.

This is perhaps unsurprising, though, because none of the rival endurance bikes feature any kind of suspension at the front end.

Although the focus on large tyre clearance and compliance pushes the Roubaix further into gravel bike territory on paper, the American brand is adamant the Roubaix SL8 is a performance road bike, first and foremost.

That said, it expects sponsored gravel racers and ultra-endurance athletes to consider using the Roubaix over the Tarmac SL8 or Aethos, while the door is open for professional road racing teams and riders to select it for the 2024 cobbled classics.

Fundamentally, Specialized has doubled down on its principle of ‘smoother is faster’, claiming the energy saved from a more forgiving ride will translate into more speed and less fatigue when the terrain is imperfect.

Future Shock 3.0 and AfterShock tech

The Roubaix SL8’s standout tech lies in the remodelled Future Shock 3.0 steerer tube suspension unit and AfterShock seatpost design.

‘Future Shock 3.0’ is the catch-all term Specialized uses for the new front damping system, but there are three specific iterations: 3.1, 3.2 and 3.3.

Future Shock 3.3 is the most advanced system found on the S-Works and Pro models. It sees a six-setting adjustable fluid damper attached to a spring.

Future Shock 3.2, found on the Expert and Comp builds, has the same fundamental design, but without the adjustable damper settings (the fluid damper is fixed in the ‘softest’ setting).

Future Shock 3.1 (featured on Sport 105, Sport Apex and ‘base’ models) relies on the sprung-loaded mechanism only – there’s no fluid damper or on-the-fly adjustability.

However, while the presence and adjustability of the fluid damper changes depending on the bike model, every Roubaix SL8 has three springs with different tensions and five preload rings, which can be used to modify the system’s sag and rebound rate.

Specialized thinks the default ‘medium’ spring will be adequate for the vast majority of riders, but the softer and firmer springs, plus the preload rings, will enable riders to fine-tune the damping to their preference.

It says the new design also makes for easier home-swapping and servicing, thanks to the spring and fluid damper now arranged with the spring on top (compared to the previous Future Shock design, where the spring was buried below the damper and required more effort to switch).

At the rear, Specialized has introduced its new ‘AfterShock’ design, which sees the seatpost clamp dropped lower into the frame to enable a new proprietary Pavé carbon seatpost to flex more.

Such a design isn’t new in the search for increased rear compliance. However, Specialized says the flexion approach (as opposed to a damped suspension system) is preferable given it offers significant deflection without markedly compromising saddle height and the relationship between the rider’s sitting position and cranks.

The system is said to offer “up to 18mm of arcing movement” in opposition to the rear axle, but only compromise saddle height by “1 or 2mm”, according to Roubaix product designer, and suspension expert, Glenn Bennett.

The seatpost clamp, which Specialized claims is positioned “65mm lower than a traditional seatpost clamp”, is adjustable via an extended Allen bolt, accessible under a rear-positioned cover.

Tyre clearance and geometry impact

Alongside the ride-damping tech in the frame, Specialized has widened clearance for 40mm-wide tyres (measured).

Despite the brand claiming the bike is designed primarily for road use, this brings it deep within the grey space between the endurance road and gravel bike genres.

This has resulted in an average 10mm increase in front-centre measurement compared to the old Roubaix (which had clearance for 33mm-wide tyres).

Elsewhere, the geometry remains focused around slack head tube and seat tube angles, with a taller stack than the Tarmac SL8.

Improved aero and low weight

Compared to the preceding Roubaix, the new bike is said to cut four watts of drag at an unspecified speed.

In context, it says 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).

The brand has reprofiled the head tube, with longer leading and trailing edges, plus deepened the fork blades to help keep airflow attached to the frame for longer.

The down tube is also deeper, while the seatstays have been dropped markedly.

Specialized product manager John Cordoba says this was initially done for aesthetic reasons (to accommodate the remodelled seatpost clamp design above the seat tube junction), but it also proved marginally more slippery in the wind tunnel.

All-in, Specialized says the S-Works Roubaix SL8 frame is the lightest in its class at 828g in a size 56cm, 50g less than the previous generation thanks to Aethos-inspired optimisations to the carbon layup.

Practicality to the fore

The Roubaix SL8 comes packaged with a suite of fixtures and fittings befitting a modern endurance bike.

The underside of the down tube plays host to a third set of bottle cage rivnuts, while the top tube has bento box mounts.

There are also front and rear mudguard mounts. These drop the tyre clearance to 35mm when suitably sized mudguards are in place.

Specialized Roubaix SL8 availability, prices and specifications

The Specialized Roubaix SL8 is available from today, in seven complete builds.

The top-spec S-Works SL8 features Specialized’s top-tier Fact 12r carbon (the previous generation topped out with Fact 11r carbon), costing £12,000/$14,000/€14,000/AU$19,900 – the same as the S-Works Tarmac SL8.

The rest of the models have framesets made using Fact 10r carbon.

The most expensive, higher-spec bikes come fitted with SRAM AXS groupsets. There’s also a Shimano 105 R7100 Di2-equipped bike, plus 105 R7100 and Tiagra/105 mix builds at the cheapest end of the range.

An S-Works frameset is also available for £4,750/$5,500/€5,000/AU$8,900, including a Future Shock 3.3 unit and headset, and Pavé seatpost.

Specialized S-Works Roubaix SL8

• Price: £12,000/$14,000/€14,000/AU$19,900
• Frame: S-Works Roubaix SL8, Fact 12r carbon
• Fork: S-Works Roubaix SL8, Fact 12r carbon
• Future Shock: 3.3
• Groupset: SRAM Red eTap AXS
• Power meter: Yes
• Wheels: Roval Terra CLX II
• Seatpost: S-Works Pavé, carbon
• Tyres: S-Works Mondo 2BR, 700x32c

Specialized Roubaix SL8 Pro

• Price: £8,000/$8,500/€9,000/AU$11,900
• Frame: Roubaix SL8, Fact 10r carbon
• Fork: Roubaix SL8, Fact 10r carbon
• Future Shock: 3.3
• Groupset: SRAM Force AXS
• Power meter: Yes
• Wheels: Roval Terra CL
• Seatpost: S-Works Pavé, carbon
• Tyres: S-Works Mondo 2BR, 700x32c

Specialized Roubaix SL8 Expert

• Price: £6,000/$6,500/€6,500/AU$9,400
• Frame: Roubaix SL8, Fact 10r carbon
• Fork: Roubaix SL8, Fact 10r carbon
• Future Shock: 3.2
• Groupset: SRAM Rival eTap AXS
• Power meter: Yes
• Wheels: Roval Terra C
• Seatpost: S-Works Pavé, carbon
• Tyres: S-Works Mondo 2BR, 700x32c

Specialized Roubaix SL8 Comp

• Price: £5,000/$5,000/€4,800/AU$7,000
• Frame: Roubaix SL8, Fact 10r carbon
• Fork: Roubaix SL8, Fact 10r carbon
• Future Shock: 3.2
• Groupset: Shimano 105 R7100 Di2
• Power meter: No
• Wheels: DT Swiss G540
• Seatpost: S-Works Pavé, carbon
• Tyres: S-Works Mondo 2BR, 700x32c

Specialized Roubaix SL8 Sport Apex

• Price: £3,250/$4,000/€4,000/AU$5,700
• Frame: Roubaix SL8, Fact 10r carbon
• Fork: Roubaix SL8, Fact 10r carbon
• Future Shock: 3.1
• Groupset: SRAM Apex AXS XPLR
• Power meter: No
• Wheels: DT Swiss G540
• Seatpost: S-Works Pavé, carbon
• Tyres: S-Works Mondo 2BR, 700x32c

Specialized Roubaix SL8 Sport 105

• Price: £3,000/$3,500/€3,800/AU$5,000
• Frame: Roubaix SL8, Fact 10r carbon
• Fork: Roubaix SL8, Fact 10r carbon
• Future Shock: 3.1
• Groupset: Shimano Tiagra R4700 (105 R7100 front derailleur)
• Power meter: No
• Wheels: Axis Elite Disc
• Seatpost: S-Works Pavé, carbon
• Tyres: Specialized Road Sport, 700x32c

Specialized Roubaix SL8

• Price: £2,500/$2,800/€2,800/AU$3,900
• Frame: Roubaix SL8, Fact 10r carbon
• Fork: Roubaix SL8, Fact 10r carbon
• Future Shock: 3.1
• Groupset: Shimano Tiagra R4700 (105 R7100 front derailleur)
• Power meter: No
• Wheels: Axis Elite Disc
• Seatpost: S-Works Pavé, carbon
• Tyres: Specialized Road Sport, 700x32c

Specialized S-Works Roubaix SL8 frameset

• Price: £4,750/$5,500/€5,000/AU$8,900
• Frame: S-Works Roubaix SL8, Fact 12r carbon
• Fork: S-Works Roubaix SL8, Fact 12r carbon
• Future Shock: 3.3
• Seatpost: S-Works Pavé, carbon