Balancing aerodynamics, weight, and affordability, the new Ultegra R8170 C50 wheelset is sure to inspire action on your group ride with its all-new tubeless carbon rim and updated, 12 and 11-speed compatible hub.

Summiting climbs, carving descents, or cruising the flats, the new C50 is the jack of all trades among the new Ultegra R8170 wheel lineup. The tubeless, carbon rim features a 21 mm internal width that pairs nicely with wider, modern tires while the HYPERGLIDE cassette body is compatible with 11 and 12-speed cassettes.

Centre-Lock Disc Rotor Mount

The Centre Lock system makes an easy rotor installation possible with a spline mount and a lock ring. The lock ring mounting system reduces the total working hours by shortening the amount of time of both installation and de-installation. In addition, the secure fixing by the spline mount enhances precision and rigidity while improving braking efficiency.

D2 Aerodynamic Rim Profile

Aerodynamic performance is affected by wind direction. To create the D2 rim, Shimano engineers considered both frontal and crosswinds, aiming to achieve optimal performance in real-world riding conditions. Extensive prototype testing, in the wind tunnel and on the road, proved that a wide rim shape with a deep tire bed performs best across a wide range of conditions. At yaw angles ranging from 0 to 15 degrees, the Shimano D2 rim profile reduces air drag better than others aero shape rims. This rim design also boosts lateral wheel stiffness and offers improved vertical compliance for increased control, comfort and durability on the road.

Shimano E-Thru Axle System

The tool-less type thru-axle skewer system optimizes rigidity and weight balance and enables easy operation with a reliable internal cam mechanism. The 15 mm thru-axle system is 15% stiffer torsionally and 25% stiffer in transverse shear than a traditional 9 mm quick release front axle system. High rigidity is secured while keeping the optimum weight balance. The E-Thru axle hub system minimizes the distortion of suspension while maintaining lightweight for riding around sharp corners at high speed. 

Rear Wheel OPTBAL Spoke System

The OPTBAL rear wheel spoke system features 21 spokes—14 on the drive side and 7 on the non-drive side. Cassette spacing in today’s wheels produces unbalanced tension in traditional 1:1 spoke systems. This unbalance is intensified with the 11-speed cassette, producing nearly double the tension on the drive side spokes. Generally, high and low tension spokes have respectively tendency toward breaking down and coming loose spoke nipples. Unbalanced tension affects durability and strength. The OPTBAL design rebalances spoke tension, enhancing wheel rigidity and strength for a more durable wheel.