The Shimano FH-RS770 is a purpose-built rear disc hub for road and gravel bikes with 12mm thru-axles. Sitting at Ultegra/GRX grade, it pairs a lightweight aluminium shell with a stainless steel HG freehub body for efficient, reliable power transfer — built for wheel builders seeking a high-quality, versatile foundation for disc road builds.

Highlights

• E-THRU thru-axle system: Shimano's tool-free 12mm thru-axle interface maximises stiffness and torsional rigidity for precise, confident handling under hard cornering.
• Centre Lock disc mount: Fast, secure Shimano Centre Lock rotor interface — simple to install and precisely centred every time.
• Stainless steel HG freehub: Compatible with 10- and 11-speed Shimano HG Road cassettes; durable stainless body resists cassette wear and deformation over time.
• Aluminium shell and axle: Weight-saving aluminium construction keeps the hub light without compromising strength.
• Cup-and-cone bearings: Shimano's proven loose-ball cup-and-cone system is field-adjustable and easily serviceable with standard tools.
• 36-hole lacing: Higher spoke count for robust, durable wheel builds — well suited to loaded touring, all-road, or heavier riders.
• J-bend spoke compatibility: Works with conventional J-bend spokes for broad spoke choice and easy wheel building.

Construction & Technology

The RS770 series sits at the Ultegra/GRX performance tier and is engineered specifically for disc-brake road and gravel applications. The hub shell and axle are machined from aluminium to balance weight and rigidity, while contact seals on both the hub and freehub body keep the internals protected from road debris and moisture. The cup-and-cone bearing system allows precise preload adjustment in the workshop and straightforward bearing replacement over the hub's service life.

Compatibility & Fit

Axle: 12x142mm (E-THRU rear thru-axle). Brake mount: Shimano Centre Lock. Freehub: Shimano HG compatible with 10- and 11-speed road cassettes. Spoke holes: 36H, J-bend. Compatible with Shimano GRX, Ultegra R8000, and other 10/11-speed road drivetrain groups. Not compatible with 12-speed drivetrains without a freehub body swap.