Specialized Roval 321 Disc 28 Inch - Rear Wheel - Clincher - QR / 12x142mm - Carbon/Gloss White

Making up about 50% of your total race time, the bike portion of a triathlon is where equipment choices can make the difference between first and fifth. And no other equipment choice will save you more time than a disc wheel. While traditionally-shaped disc wheels are faster than their spoked counterparts, the Roval 321 Disc for disc brakes turns conventional design on its head, creating the fastest wheel on the planet.

Specialized Roval 321 Disc Brake features:

• Rim Type: Full carbon clincher, 2Bliss Ready
• Rim Material: Carbon
• Braking Surface: Disc brake only
• Rim Depth: Solid Disc
• Rim Width: 19mm internal, 27.3mm external
• Rear Hub: Roval Disc 142x12mm, CeramicSpeed bearings, DT Swiss 240 internals, 11-speed
• Assembly Method: Handmade

Disc wheels often fall into two categories—a completely flat shape, with structure coming from carbon fibre and a honeycomb-foam filling, or a spoked wheel that's been faired with a carbon fibre cover. In our quest to break traditions, the 321 uses a single layer of 1k carbon fibre on each side of the wheel, and it all comes together at the brake track bridge. This kind of carbon fibre is rarely used in bicycle components due to its high manufacturing cost, but it offers a bevy of performance benefits. This coveted carbon is much lighter than other layups, like 3k and 12k, and it can only be laid by the most skilled of carbon fibre craftsmen. It's complicated, but the pay-out is worth it, as it delivers a supple ride and one of the lightest disc wheels available. And in the real world, this means that it'll spin-up quickly and reduce fatigue over the long haul.

Stiffness is often the "hot-topic" in the disc wheel world, but Specialized think it's an interesting conversation. It's long been thought that efficient power transfer and high stiffness are directly correlated, but through extensive field testing, they've determined that this isn't the case at all. In fact, their initial disc was so stiff that, under power, it wouldn't flex with the frame and this caused brake rub. This wrongly creates the perception of a flexy wheel, when really, the wheel is actually too stiff. In order to solve the brake rub problem, Specialized first designed their optimal aero shape and then worked on their internal stiffness targets to fit within what Specialized consider to be a desirable frame stiffness.

And while light overall weight was a development priority, Specialized´s focus was aerodynamics. Through hours of Computational Fluid Dynamics (CFD) and testing in the Win Tunnel, they developed a never-before-seen shape that's optimized to work with a tire for on-bike airflow. What this translates to is an all-carbon disc wheel that, on the non-drive-side, has a shape that's as aerodynamic as their current understanding allows, and a drive-side shape that's as aerodynamic as the wheel-dish and derailleur clearance will allow for.

To save every possible watt, Specialized has also added CeramicSpeed bearings and DT Swiss 240 hub internals into their hub. Each 321 Disc wheel is also 2Bliss-Ready out of the box and comes with a quick-release, and tubeless valve stem.

Designed for the most uncompromising athletes in the world, with engineering to match, the 321 Disc is the world's most advanced disc wheel for your race against the clock.