Specialized S-Works Roubaix SL4 Disc Review

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If you followed Eurobike and Interbike last month you would have seen that all the major road bike brands are moving full steam ahead when it comes to disc brake models. In this piece we review the Specialized Roubaix S-Works Disc and put it through its paces.

Specialized’s Roubaix S-Works is the bike Tom Boonen rode on his way to his fourth Paris-Roubaix title last year. The Roubaix model is positioned in Specialized’s “Endurance” range rather than its “Competitive Road” line-up, but as I found out, the bike screams to be pedaled in anger. Okay, that’s a bit overdramatic…

Before the ride

The Roubaix S-Works is built up with SRAM Red-22 with S-Works bar and stem along with the CG-R seatpost (CG stands for “COBL GOBL-R” or “Cobble Gobbler”). The CG-R has 18mm of vertical dampening to take the edge off everything from rough roads to the Koppenberg.

The frame is made from Specialized’s FACT carbon and is equipped with the “Zertz” system to create an incredibly smooth ride. The “Zertz” vibration dampeners are just that. It’s a common misconception that these provide a sort of suspension for the bike but if you look underneath the elastomer fixtures you’ll simply see more carbon fibre.

As a demonstration of how these work, look (or rather listen) to this video:

The video shows the difference between having no dampener (first) and the Zertz dampener (second) when being dropped on the floor.

The wheels are Roval Rapide CLX40 carbon clinchers with ceramic bearings paired with S-Works Turbo 26c tyres. The fork provides ample tyre clearance and would fit 28mm tyres. The 26mm tyres are definitely big, but they give you the confidence to seek out those rough roads and gravel paths to create your own adventure.

Note: I’m still awaiting an answer from Specialized regarding the structural considerations taken into the fork due to the new power the disc brakes enable.

Hydraulic Discs

The hero of this bike is the SRAM Red hydraulic disc brakes. It’s the first time Specialized has put a disc brake on one of their high-end road models, and they couldn’t have picked a better fit than the Roubaix.

Rather than getting into a debate here about whether disc brakes are the right or wrong technology for road bikes, refer to this post that we wrote yesterday on the future of disc brakes.


The Roubaix’s geometry is best described as “relaxed” and is now typically considered to be an “endurance” geometry.

The chain stays are quite long resulting in a wheelbase 2.5cm longer than the same size (56cm) Tarmac. There is also much more fork rake than the Tarmac and the bottom bracket is quite high (which makes it a fast handling bike), and the head tube is massive 3cm taller and slacker by one degree. This translates more weight in the saddle and less of a reach to the bars (for those of you who like to site more upright, this is good).


For more information on how to interpret geometry charts, click here.

The remainder of the S-Works Roubiax SL-4 Disc design features include the S-Works SL4 FACT carbon construction, tapered 1-1/8” headtube, internal cable routing, and oversized integrated bottom bracket (OSBB, Specialized’s version of PF30) with ceramic bearings.


Specialized has a total of nine Roubaix offerings and the Roubaix Disc is also offered in its “Sport” model which features SRAM hydraulic disc brakes and SRAM Apex (10-speed) components.

The bike weighs a total of 7.1 kilograms (without pedals) and the suggested retail for Australian buyers is $8,499.

For more information on the Roubaix, refer to the Specialized website.

After the ride

I have to admit that I didn’t care for the Roubaix that I test rode last year. I felt far too upright and perhaps, and excuse the expression, “like an old man”. Perhaps it was the setup, but it just didn’t feel agressive enough for me. The Tarmac was the bike for me, but this time around I got a completely different impression.

This Roubaix fit and felt like a race bike with the ride comfort of a mountain bike. The Zertz combined with the Cobble Gobbler seatpost and 26mm tyres created a remarkably smooth and quiet ride which dampened out all vibrations.


The ride is smooth as butter without feeling soft or wasteful. In fact, when I got out of the saddle and kicked, the bike gave up nothing in terms of efficiency and didn’t feel like an “endurance” bike whatsoever.

My only criticism would be that the CG-R seatpost is perhaps more responsive that what the front end of the bike is built to handle and there’s a slight feeling of imbalance between front and rear compliance when on very rough roads (i.e. my cobbled back lane).

This particular Roubaix weighs in at 7.1kg and while this isn’t light by today’s standards, I thought it would be heavier. When you look at and sit on the bike it looks “beefy” with the 26mm tyres, disc brakes, and enormous brake hoods. However, the way it handles feels light and nimble but as grounded as a cyclocross bike.

The SRAM hydraulic levers do look somewhat odd with their bulk protruding towards the sky, and they do feel a bit “off” when you first lay your hands on them. However, the surface area for your hands is actually identical to the regular RED brakes. They feel “chunky” but as I quickly got used to them, I began to really like that stable feel. My immediate thought was that these would be awesome on a cyclocross bike (stay tuned for a CX bike review featuring these brakes. I’ve been having a hoot on this bike).


There’s no doubt that the disc brakes provide a leap in performance over calliper brakes. The difference was most profound when I hopped back on my regular bike after reviewing the Roubaix and felt how sluggish my calliper brakes were. It’s a similar sensation to going from electronic shifting back to mechanical; you wonder how you survived without it.

Descending on the Roubaix was a treat. Once I gained some confidence with the stopping power of the discs I felt like I was in better control when entering the corners. The “feel” of having the stopping power come from the middle of the wheel rather than from the outside of the wheel is outstanding.

In my experience, most crashes happen as a result of locking up the front wheel when going around a corner. With the improved modulation that disc brakes offer, even though they’re more powerful, my feeling is that the chance of this scenario is reduced because of their linear stopping power.

The Roval Rapide wheels themselves are especially good. I’m not convinced on carbon clinchers (because of braking issues and heat build-up) but the disc brakes get rid of both those issues. Ever since I first rode Roval wheels I’ve been a fan.


Final Thoughts

I only got to ride this bike twice for a total of 150km and I wasn’t eager to give it back. It’s a seriously fun bike to ride and awakened my sense of adventure. Gravel roads, cobbles, mountain passes and descents … that’s where I want to take this bike.

I wouldn’t recommend buying this if you’re looking for a fast criterium race bike, but it would be a joy to pedal on long, hilly rides or sportif events (unsanctioned by the UCI because of the disc brakes, of course).

Although the disc brakes provide much better braking performance I’m still not ready to part ways with my proud collection of legacy race wheels and render them obsolete by upgrading to discs. That said, if I had the money to spend I could easily be convinced.

Thank you to Specialized for supplying this bike for review. Full disclosure: Specialized advertises with CyclingTips.

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