Description
Carbon gravel wheels have become essential equipment for serious mixed-terrain riders, and Shimano’s GRX WH-RX870 TL Disc Wheelset marks the brand’s first carbon entry in the gravel category. The wheelset applies the same engineering philosophy that defines the GRX component line: purpose-built for off-pavement use rather than adapted from road designs. Where road carbon wheels prioritize aerodynamics and outright weight savings, the RX870 balances those concerns against the durability demands of rough surfaces, low tire pressures, and unpredictable terrain that define gravel riding.
The full carbon rim measures 32mm deep with a 25mm internal width, dimensions that reflect Shimano’s research into the relationship between rim profile and tire stability at lower pressures. Wider internal channels support wider tires without the sidewall flex that compromises handling when pressures drop into gravel territory. The external width of approximately 30mm creates a smooth transition from rim to tire that improves aerodynamics across a range of setups. The RX870 accommodates tires from 32mm to 50mm, covering everything from fast-rolling gravel race rubber to high-volume adventure tires suited for bikepacking. A hooked bead design provides compatibility with both tubeless and tube-type setups, and the wheelset ships with tubeless tape and valves installed.
Hub construction follows Shimano’s established approach with cup-and-cone bearings rather than sealed cartridges. The cup-and-cone system offers complete serviceability and adjustment without specialized tools. The GRX-specific aluminum hubs feature Contact seals that resist debris and water intrusion while remaining accessible for maintenance and bearing replacement. Straight-pull flanges anchor 24 bladed, double-butted stainless steel spokes per wheel in a symmetrical 2x/2x lacing pattern. The spoke interface at the hub allows controlled movement that distributes impact forces rather than transferring them directly to the rim, providing a measure of forgiveness on rough terrain…. Read More
The rear hub uses a steel freehub body that resists cassette bite-in from aluminum cogs under load, a consideration for riders who swap cassettes frequently or run aggressive gear ratios. An 18-point ratchet system provides 20 degrees of engagement, adequate for gravel and cyclocross applications though riders accustomed to high-engagement mountain bike hubs may notice the difference on technical terrain requiring quick power application. External alloy nipples simplify tension adjustments and truing when the wheels need service. The HG freehub body accepts both 11 and 12-speed road cassettes with appropriate spacers, maintaining compatibility across Shimano’s current drivetrain range.
Center Lock rotor mounting and 12mm thru-axle spacing (100mm front, 142mm rear) follow current gravel standards. At 1461 grams for the pair, the RX870 positions itself as a performance option that prioritizes long-term reliability over extreme weight reduction. The wheelset reflects Shimano’s broader GRX philosophy: gravel-specific engineering that delivers durability and value without sacrificing the responsiveness that makes carbon wheels worth the investment.
