Specialized Tarmac Disc

Specialized's flagship race bike now comes in a disc brake-equipped version.​

As the WorldTour pro peloton eases ever deeper into disc brake use (just as most consumers did a while ago), it comes as no surprise that Specialized's flagship race bike is now available with rotors, too. Indeed, the California-based bike maker recently released S-Works versions of its popular Tarmac platform, and we'd expect more budget friendly options are not far behind.

Specialized Tarmac Disc

Max tire clearance is listed at 30mm. The stock setup is 26mm.​

For now, though, you'll need to pony up a big wad of cash if you want disc brakes on a Tarmac. Fully loaded men's and women's models both sell for $11,000, or you can opt for frame and fork - $5000 for the ultralight black-silver version, or $4500 for the standard S-Works frameset, which comes in acid mint and turquoise camo, chameleon-acid red, chameleon-cyan, or flo red-metallic-white-black.

Specialized Tarmac Disc

The full array of frame color options.​

Before you balk at that complete bike price, know that this top-shelf build includes the new dual-side-measuring S-Works Power Cranks powermeter, which we'll touch on more in a moment. The rest of the build is highlighted by Shimano Dura-Ace Di2 9150 drivetrain and Roval CLX 50 Disc tubeless-ready carbon wheels. Here are the complete specs for both the men's and women's builds.

Specialized Tarmac Disc

Specialized Tarmac Disc men's build specs.​

Specialized Tarmac Disc

Specialized Tarmac Disc women's build specs.​

This bike is also light and fast, says Specialized, which gave RoadBikeReview a quick sneak peek back in February. Utilizing upwards of 500 carbon plies, the S-Works Tarmac Disc is billed as the company's lightest frame, coming in around the 800-gram mark, they say. It also continues to implement Specialized's rider first engineering, which simply means that subtle lay-up changes are made in the various frame sizes so as to deliver the same ride quality across the line, rather than say a really stiff size small, but a more noodly XL.

Read RoadBikeReview's First Ride Review of the Tarmac SL6 rim brake bike, which shares frame technology with the newly released disc-brake equipped model.

Specialized Tarmac Disc

Save for slightly longer chainstays, the bike's frame is essentially identical to its rim brake-equipped cousin.​

Size options for what is officially known as the Tarmac SL6 Disc are 49cm, 52cm, 54cm, 56cm, 58cm, and 61cm. Women can choose from 44cm, 49cm, 52cm, 54cm, and 56cm, and there are three different fork sizes used within all these sizes to further nail handling characteristics, which as you'd expect are billed as snappy, fast, and stable. Geometry is the same for both men and women (and only the 410mm chainstays differ from rim brake model at 5mmm longer). Otherwise the geometry is identical between rim and disc and men's and women's, with only touch points and frame color differing. Here's the complete geo chart.

Specialized Tarmac Disc

Specialized Tarmac Disc frame geometry chart.​

Specialized also claims that testing in its cheekily named Win Tunnel revealed no aerodynamic penalty when compared to the rim brake-equipped Tarmac. Other features of the frame include 12mm thru axles that are thinner, meaning they are flush to the frame on either end. It also has flat mount disc brakes, and a D-shaped seat post that has been "tuned", which is said to deliver a touch of backward flex at the top of the post to smooth out rough roads. You can further soften your ride with clearance for up to 30mm tires, through the stock setup is 26mm 320tpi S-Works Turbo cotton clinchers.

Specialized Tarmac Disc

12mm thru axles are flush to the frame, minimizing drag.​

Overall bike weight for the $11k build is claimed to be 14.65 pounds size 56cm, which compares favorably to the analogous rim brake bike at 14 pounds even. (And remember that includes the powermeter). Of course, that's with the lightweight paint. Choose something besides black-silver and your ride will gain about 150 grams.

To learn more, click over to page 2 of this post for an extensive FAQ on the new bike, and log on to www.specialized.com.

Specialized S-Works Power Cranks

Meet the new S-Works Power Cranks dual-sided powermeter.​

S-Works Power Cranks Powermeter

As already mentioned above, these top-end builds come stock with Specialized's just launched S-Works Power Cranks dual-side-measuring powermeter, which gives the Big Red S the distinction of being the first major bike maker to have its own powermeter. Though it must be noted that they've partnered with 4iiii in the manufacturing of some of the internals.

Specialized S-Works Power Cranks

This giant treadmill was integral in validating the new meter's accuracy.​

The project was about 3 years in the making, with a focus on accuracy across all riding scenarios. That quest for near-perfection actually led to an about face on the original launch date, which was supposed to be late last summer. But some issues with thermal drift in the carbon cranks sent the design team back to the drawing board and only now have they been released to the wider world.

Specialized S-Works Power Cranks

University of Colorado professor emeritus Rodger Kram, an expert in quantifying human locomotion, led the validating team.​

The project also led to one of the more interesting test setups we've encountered. Partnering with University of Colorado professor emeritus Rodger Kram, an expert in quantifying human locomotion, Specialized funded the building of what amounts to an oversized treadmill for bikes. The driver was that instead of simply relying on a dyno to measure accuracy, they wanted to be able to test their new meter in more real world conditions using this force-measuring treadmill that's located on the CU campus in Boulder.

Specialized S-Works Power Cranks

Aftermarket options will include a dual sided Dura-Ace model.​

Without going too far down the mad science rabbit hole, Specialized says the project allowed them to verify accuracy and that their new meter by looking at rider and bike weight, drivetrain efficiency, tire rolling resistance, gravity, and speed, while also taking into consideration other factors such as cross chaining, cadence changes, and temperature fluctuations. What it found is that their new meter "is the most accurate on the market." RoadBikeReview obviously can't verify that claim at this point, so take it however you like. But safe the say the giant treadmill and the work that went into this project was undeniably impressive.

Specialized S-Works Power Cranks

There will also be a single-sided Ultegra upgrade.​

The new meter communicates over the standard ANT+ and Bluetooth wireless protocols, so no need to buy a new computer head unit. It will be available both aftermarket and as a spec option on higher end Specialized bikes. Pricing for the S-Works cranks model is $1150 dual, or $750 for a single sided version. There will also be an S-Works Dura-Ace 9100 Dual model for $1500, an Ultegra left crank upgrade for $525, and a Shimano 105 left crank upgrade for $425. The S-Works Dual has a carbon spider, hollow carbon arms, and an alloy spindle, while the S-Work Single has an alloy spider. Shimano Specialized Power cranks will come in 170-175mm lengths, while the S-Works Power cranks run 165mm-180mm. The meter is operated via an app that once paired can handle zero offsets and other simple diagnostic functions. Here's a complete rundown of features

  • Works with ANT+ and Bluetooth devices
  • Easy set-up and diagnostics with the Specialized Power app
  • Hollow carbon crankarms, carbon spider, and oversized alloy spindle
  • Claimed weight 440 grams for 172.5mm crankarm length
  • Fits Specialized road frames with OSBB or PF30 bottom bracket shell
  • Also fits most BB30 road frames
  • 110 BCD carbon spider (also compatible with 130 BCD carbon spider-sold separately)
  • Compatible with Shimano and SRAM drivetrains
  • Chainrings are sold separately. Use only with Specialized/Praxis chainrings 52/36T or 50/34T
  • Available in 165-180mm crankarm lengths

To learn more, power over to www.specialized.com.

Continue to page 2 to read a Specialized Tarmac SL 6 Disc FAQ

Specialized Tarmac SL 6 Disc FAQ

Specialized Tarmac Disc

Ultralight black-silver painted version.​

Is the Tarmac Disc more or less aerodynamic than the rim brake version?
The rim and disc bikes are aerodynamically identical. We've been working on disc brake road bikes for over five years and can therefore make a disc-equipped bike that has zero detriment to aerodynamic performance.

Are there any geometry changes?
The Tarmac Disc geometry is exactly the same as the Tarmac Rim, and it uses our new shared platform geometry developed with data from Retül. The only difference between the rim and disc brake bikes is the chainstay length. The rim bike chainstay length is between 405 and 410mm depending on frame size, while the disc brake bike is 410mm for all frame sizes.

Specialized Tarmac Disc

The women's Specialized Tarmac SL 6 S-Works Disc.​

How does the weight compare? Rim to disc frames and complete bikes? What is the exact weight of the frame/fork?
The S-Works Tarmac Disc frame is as light as 800g in a size 56cm depending on the exact paint color. The fork weight is approximately 338g. Please note that the fork was designed for stiffness and aerodynamics, as opposed to chasing light overall weight. The fork design has a very significant and positive impact on the handling of the bike. The complete bike weight (no pedals, size-/paint-dependent) for an S-Works Tarmac Disc is approximately 14.65lbs (6.65kg). The S-Works Tarmac Rim weighs approximately 14lbs (6.36kg). The Disc weight also includes the S-Works Power Cranks.

Does the frame stiffness and handling change between rim and disc brake bikes?
No. We designed for the exact same Rider-First Engineered™ targets regardless of brake system.

Specialized Tarmac Disc

Acid mint and turquoise camo frame color.​

Are there differences in the Rider-First Engineered philosophy and construction between the rim and disc versions?

What models will the Tarmac Disc be available in?
When we went live on March 14th, the story will be the Men's and Women's S-Works Tarmac Disc and the S-Works Tarmac Disc frameset. This summer, we'll announce more models, but for now, the story will be focused on S-Works.

Specialized Tarmac Disc

Chameleon-cyan frame color.​

When will bikes be available?
The S-Works models are available now.

Are there differences between Men's and Women's frames?
No. All frames are designed with input from Retül data to create the best platform for all riders, regardless of gender. Framesets are sold in all colors and all sizes. Complete bikes are offered in Women's and Men's versions. The frames are identical, while the saddle model, bar width, and crankarm length are optimized for Women's and Men's models.

Specialized Tarmac Disc

Chameleon-acid red frame color.​

What is included in a frameset purchase?
Frame, fork, headset, seatpost, CeramicSpeed BB30 bearings, and all small parts, like cable routing items, a seat clamp, and a rear derailleur hanger.

What is the "Flush Axle System?"
We offer a "flush" axle that sits flush with the frame and requires the use of a 6mm Allen wrench to remove the axle. The bikes and frames come with two sets of axles-DT RWS levers and flush, bolt-on axles. The flush bolt on axles are 30g lighter per axle than the RWS version.

Specialized Tarmac Disc

The hydraulic brakes are flat mount.​

What is the axle spacing of the bike?
The front is 12x100mm and the rear is 12x142mm.

What wheels are compatible with the Tarmac Disc?
Any 700C disc brake wheel that can be setup with 12x100mm front and 12x142mm thru-axle rear spacing. There are many options on the market, though we highly suggest that riders use Roval wheels, as they're class-leading in weight and aerodynamic performance. There's nothing proprietary about the axle size/spacing, and there are many wheel options.

Specialized Tarmac Disc

That's the new Specialized S-Works Power Cranks powermeter.​

What is the tire clearance? Production and aftermarket?
The S-Works bikes ship with a 26mm Turbo Cotton tire, but the frame will accept tires that measure up to 30mm-wide when installed and inflated. An example of this is a 28mm Turbo Cotton installed on a CLX 50 Disc.

Specialized Tarmac Disc

Boels-Dolmans Cycling Team frame color.​

What professional athletes/teams will use the bike? Triathletes?
The first athletes on the S-Works Tarmac Disc will be our three professional road race teams - Boels-Dolmans Cycling Team, Quick-Step Floors Cycling Team, and Bora-Hansgrohe Cycling Team. We will also provide the S-Works Tarmac Disc to our ITU triathletes. The exact roster and timing is to be determined.