Shimano's first purpose-built carbon gravel wheel, the GRX WH-RX870, delivers a refined balance of low weight, compliance, and confident handling across mixed terrain. With a 32mm-deep full-carbon rim and a 25mm internal width optimised for 32–50mm tyres, it keeps tyre lateral stability high even at the lower pressures that gravel demands — all at an 822g rear weight.

Highlights

• Full-carbon rim: 32mm depth with 25mm internal / 30.7mm external width for optimal tyre support on 32–50mm rubber.
• Tubeless-ready: Hooked bead construction seals tubeless tyres securely; rim tape required (not included).
• 24 straight-pull bladed spokes: Butted stainless steel spokes reduce weight and aerodynamic drag while maintaining long-term durability.
• 12mm E-THRU thru-axle: 142mm O.L.D. rear spacing for modern gravel and endurance disc road frames.
• Centre Lock disc: Clean, precise rotor attachment; compatible with 6-bolt adapters (adapter sold separately).
• HG freehub: Accepts Shimano 11- and 12-speed road and gravel HG cassettes (GRX, Ultegra, 105).
• Cup-and-cone bearings: Field-serviceable bearing system with contact hub seal for long-term reliability.
• Lightweight at 822g: Rear wheel weight suitable for all-day gravel and mixed-surface riding.

GRX Carbon Rim Design

The WH-RX870's carbon layup has been tuned specifically for gravel riding — balancing vertical compliance to absorb trail chatter with lateral stiffness for efficient power transfer. At 32mm deep, the rim profile keeps handling predictable in crosswinds while still offering modest aerodynamic benefit on faster gravel sections. The wider 25mm internal width allows the tyre casing to open up fully, improving traction and reducing pinch-flat risk when run tubeless.

Tubeless-Ready Construction

The hooked-bead tubeless rim design allows a secure tyre seal without an inner tube. Rim tape is required (not included). The system supports tyre widths from 32mm to 50mm, making it suitable for everything from hardpack gravel to rougher mixed-surface riding. Running tubeless with sealant reduces rolling resistance and allows lower pressures for improved grip and comfort.

Compatibility & Fit

This rear wheel accepts Shimano HG cassettes for 11- or 12-speed road and gravel drivetrains (e.g. GRX, Ultegra, 105). It is not compatible with Shimano Micro Spline or SRAM XDR cassettes. Brake rotor attachment uses Centre Lock (rotor not included — a lockring tool is required for installation). The 12×142mm E-THRU axle suits most modern gravel and endurance disc road frames. Verify your frame dropout spacing before purchase.