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 a 822g rear weight.

Highlights

• Full-carbon 32mm-deep rim with 25mm internal / 30.7mm external width
• Tubeless-ready hooked bead construction
• 24 stainless steel bladed, butted straight-pull spokes
• 12mm E-THRU thru-axle hub, 142mm O.L.D. rear spacing
• Centre Lock disc brake compatible
• HG-11 freehub — compatible with Shimano 11- and 12-speed road/gravel HG cassettes
• Cup-and-cone bearings with contact hub seal
• Optimised for 32–50mm tyre sizes
• Rear wheel weight: 822g

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 12x142mm E-THRU axle suits most modern gravel and endurance disc road frames. Verify your frame and fork dropout spacing before purchase.