Finally with disc brakes! After presenting the fully-revised version of the Tarmac last year, Specialized is now introducing their new S-Works Tarmac Disc 2018. In this exclusive test we had the opportunity to ride the brand new disc-version and compare it against its rim brake antagonist.

Specialized S-Works Tarmac Disc vs Rim
In this exclusive test we had the opportunity to compare the disc and rim versions of the Specialized Tarmac 2018.

If you missed the full review of the Specialized S-Works Tarmac 2018 rim-version, here is a little refresher: regardless of whether you’re pelting at 40 km/h on the flats, slowly climbing a mountain pass or blasting fast descents in your best aero-tuck, the Tarmac always feels precise and radiates an innate calmness, remaining reassuringly predictable and composed at all times but without feeling sluggish. Light-footed, stable, confidence-inspiring? Check!

Specialized S-Works Tarmac Disc 2018 – sind Scheibenbremsen besser?

The engineers at Specialized took almost a year to develop the new Tarmac Disc. Their top priority was maintaining the superb riding characteristics of the rim version. Did they succeed? We’ve found the answer with the hip-hoppers from Black Sheep.

First Ride Review: Specialized S-Works Tarmac Disc 2018

Specialized Tarmac Disc models & prices

The Specialized Tarmac Disc will be available from March the 14th 2018 – but only in the S-Works version and at a price of € 9,999, which is exactly the same of the rim-version. Specialized is also releasing an S-Works Tarmac Disc frameset and planning to present even further models later this summer. The Women/Men models share the same frame with the only difference being the saddle, cockpit and crank lengths.

Specialized S-Works Tarmac Disc im Detail

Drivetrain Shimano Dura-Ace Di2
Brakes Shimano Dura-Ace Di2
Wheels Roval CLX 50 Disc Carbon
Tires Turbo Cotton 700 x 26
Weight 6.69 kg (56 cm)
Price € 9,999

Erster Test: Specialized S-Works Tarmac Disc 2018
The disc model allows for tire widths of up to 30 mm
As with the rim version Specialized renounced an integrated cockpit on the Tarmac Disc
The Specialized S-Works Tarmac Disc comes with an integrated watt-meter: the Specialized S-Works Power Cranks measure on both sides and are said to be extremely precise. According to Specialized the rim-version of the Tarmac will soon feature serial Power Cranks.
Clever and pretty: theDi2 Junction Box hides in the bar-ends.
The Tarmac disc doesn’t make any unpleasant rattling noises but the cable routing could be a little tidier
Sexy and fast: 26 mm wide Specialized Turbo Cotton tires on 50 mm deep Roval CLX 50 Disc wheels.
Specialized relies on a Shimano Dura Ace Di2 groupset for the new Tarmac Disc
Ceramicspeed bearings for maximum smoothness – we like it!
Clean and simple: the cover on the integrated saddle clamp

Specialized Tarmac Disc geometry & sizing

The women’s and men’s models come respectively in six sizes (49,52,54,56,58,61). The disc version features the same geometry as the rim model, only the chainstays are 5mm longer on smaller frame sizes.

Size 49 cm 52 cm 54 cm 56 cm 58 cm 61 cm
Seat tube 431 mm 462 mm 481 mm 501 mm 522 mm 553 mm
Top tube (horizontal) 508 mm 531 mm 540 mm 562 mm 577 mm 595 mm
Head tube 115 mm 126 mm 143 mm 163 mm 190 mm 210 mm
Head angle 71.7° 72.5° 73.0° 73.5° 73.5° 74.0°
Seat angle 75.5° 74.0° 74.0° 73.5° 73.5° 73.0°
Chainstay 410 mm 410 mm 410 mm 410 mm 410 mm 410 mm
BB Drop 74 mm 74 mm 72 mm 72 mm 72 mm 72 mm
Wheelbase 973 mm 975 mm 978 mm 990 mm 1005 mm 1012 mm
Reach 375 mm 380 mm 384 mm 395 mm 402 mm 408 mm
Stack 514 mm 527 mm 544 mm 565 mm 591 mm 612 mm

Weight of the Specialized Tarmac Disc

The Specialized S-Works Tarmac Disc in our test weighs 6,69 kg while the S-Works Tarmac rim model with identical spec reads 6,38 kg on our scales. This means a difference of 310 grams between the two fully built bikes (both in a 56 cm size). The frame alone of the disc version is a just 67 g heavier than the rim model. With a weight of 800 g in a 56 size the Specialized Tarmac Disc has done itself proud!

Still the most effective way to save weight;)

Test Specialized Tarmac Disc vs. Rim

Let’s be honest, many disc race bikes often feel sluggish and cumbersome! A lot of bikes that were originally designed to work with rim brakes are only given basic facelifts and adapted with minimal modifications to be compatible with disc brakes. This can cause the bike to be less direct and more difficult to control than models with rim brakes. This is mainly due to the fact that disc brakes produce stronger forces and greater leverage than rim brakes.

Deceptive romance at Solitude Castle in Stuttgart, Germany: The two Specialized Tarmac racers are ready for a street fight.

But these problems are alien to the new Specialized Tarmac Disc! Most people wouldn’t even be able to tell the difference between the two bikes if riding blindfolded.

Only a direct comparison revealed some minimal differences: the front-end of the disc model feels a little more composed (but in no way sluggish!) and at the same time stiffer and more defined, which is imputable to the reinforced disc fork. The combination of a 160 mm disc at the front, a 140 mm rotor on the rear and the Shimano Dura-Ace Di2 disc brakes delivers incredibly well balanced braking power. And despite a light squeaking noise in wet conditions they still feel more consistent, intuitive and reliable than any rim brake in changing weather conditions. Even when decelerating hard the Tarmac Disc stays in control and shines with its precise, superb handling; this is somewhat surprising considering its slender shape. The bite point of disc brakes is way more appealing than the slightly delayed and sometimes more undefined touch of rim brakes due to stretching cables.

Many of us are still wondering whether road bikes can actually fully take advantage of the enormous power of disc brakes or if it’s all just a massive waste of technology. The answer is yes they can! Our tests in dry conditions revealed a difference in braking distance of around 10% between the disc and rim versions. Having said your braking skills also play a crucial role. Shifting your weight backwards while braking will increase the traction on the rear wheel and also allow you to squeeze the front brake harder without flying over the bars.

Conclusion Specialized S-Works Tarmac Disc

The new Tarmac Disc fills an important gap in Specialized’s portfolio, something we’ve been waiting to happen for a long time. So what’s the verdict then, discs or rim? Lower weight, easier handling and a classic look are good points in favour of rims. On the other hand the disc version of Specialized’s black racing-horse offers better control and more confidence. The price is the same and the performance is pretty much identical. We leave the final word to the legendary Black Sheep hip-hoppers: The choice is yours! If you can afford it take both – like our editor Manuel: Thug Life!

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Words: Robin Schmitt Photos: Valentin Rühl, Robin Schmitt