Specialized has today released a disc version of the flagship S-Works Tarmac SL6, which comes complete with Specialized's new crank-based S-Works power meter. At a weight of 6.65kgs is on par with the very lightest disc-brake equipped bikes on the market.
Specialized has been a champion of the disc brake on road bikes from the outset, with the Venge VIAS series now available only with disc brakes bolted on, so this release has been long expected – especially given the popularity of the SL5 generation Tarmac disc.
The new Tarmac disc has already made an appearance at some smaller spring races by Specialized-sponsored teams. There’s every chance it may appear at the larger Spring Classics in place of the Roubaix for some of Specialized’s riders.
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Rim rival
This SL6 S-Works Tarmac disc is extremely similar in overall performance and construction to the rim brake version, while looking starkly different to the SL5 generation.
The geometry is identical to the rim brake version, which has been a strategy employed by Specialized since its use of SCS (Short Chainstay System) technology to shorten disc chainstays, where wheels would be uniquely dished to avoid affecting the chain line.
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Despite using the same philosophy, the Tarmac disc no longer needs specific Roval wheels as in previous generations, and will be compatible with any road disc wheels.
Specialized has excitedly revealed that the disc version boasts the exact same overall aerodynamic performance as the rim version. The frame itself comes in at around 800g in a size 56 – within 50g of the rim version.
As with the Tarmac's rim brake version, handling is a key target, and Specialized claim the bikes will handle identically, only with the added advantages of braking control, modulation and power associated with disc brakes.
Lightweight
Strikingly, Specialized boasts a total weight for the top spec 56cm S-Works Tarmac disc to be only 6.65kgs. That makes it one of the lightest mass production disc brake road bikes ever produced, while still boasting aerodynamic performance equal to the last generation Specialized Venge.
Over a 40km time trial at 40kmh the Tarmac disc should save over 45 seconds compared to major endurance race rivals with a rim-brake spec.
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The discs have brought with them the advantages of extra stopping but also tyre clearance. The Tarmac SL6 has been specced thus far with 26mm S-Works Turbo Cotton tyres that measure closer to 29mm in width. The disc version will easily fit 28mm from any brand and as large as 30mm for some tyre-rim combinations.
Power
The bike will come as standard with Specialized’s new S-Works Power Meter, which is adapted from a 4iii system and will be mounted on the spider and crank arm within the crankset with a claimed accuracy of +/- 1%.
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The dual-sided power meter adds only 15g compared to a normal S-Works crankset, and strikingly comes in 100g lighter than a power-meter equipped Shimano Dura-Ace crankset.
As the weight comes in below the 6.8kg UCI minimum weight, we might expect pros to be using the disc version for upcoming races. The bike has already been provided to all of Specialized’s major men’s and women’s teams.
We are unfortunately yet to get our hands on a rideable sample of the S-Works Tarmac disc, but will soon be able to give the bike a full in-depth long-term test.
The bike is available for purchase from today, and will retail for £9,250 with an S-Works Power meter, Shimano Dura-Ace Di2 and Roval CLX 50 carbon rims.
