Reynolds ATRx 650b Tubeless Disc Wheelset

The Reynolds ATRx 650b Tubeless Disc Wheelset is Reynolds' interpretation of All Terrain Road built for the 650b format — a wheelset that applies the aero-gravel engineering of the ATR line to a 27.5" platform designed for riders who want maximum tire volume without sacrificing forward speed. ATR stands for All Terrain Road, and the premise is straightforward: take the aerodynamic profiling and lightweight carbon construction that makes road wheels fast and engineer them to work with the larger tires, varied terrain, and mixed-surface demands of modern gravel riding.

Reynolds builds the ATRx rims using their CR6 layup process — a carbon construction method optimized for the balance of low weight, stiffness, and durability that an all-road wheelset requires. At 40mm deep on a 650b platform, the rim profile is aerodynamically shaped using Reynolds' RAV design approach, which accounts for real-world wind angles rather than just straight-line tunnel data. The rim's snub-nosed, wide aero profile was developed specifically around larger tire widths, so the transition from rim to tire is smooth rather than abrupt — a geometry that matters for aerodynamic behavior when running 40mm-plus gravel tires. Reynolds backs the structural integrity of these rims with a lifetime guarantee.

The rim measures 23mm internal and 32mm external — wide enough to properly seat contemporary tubeless gravel tires and allow them to develop the rounded casing profile that reduces rolling resistance and improves cornering stability. The hooked bead design is compatible with a wide range of tubeless tires and supports a broader tire pressure range than hookless rims, making the ATRx usable across more tire options and more conditions. Tire compatibility runs from approximately 40mm to 50mm on a 650b rim, allowing you to run a large-volume gravel setup that handles rough roads, chunky gravel, and light trail surfaces with equal composure.

At the hub, Reynolds uses the Allroads Disc — a CNC-machined hub with 36 points of engagement at 10-degree increments. 36 points of engagement means the freewheel engages every 10 degrees of pedaling, which translates to fast pickup out of technical corners and tight switchbacks. Center lock disc brake interface keeps rotor mounting clean and secure across the front and rear. The front axle accepts 12x100 or 15x100 configurations; the rear runs 12x142, covering the full range of thru-axle disc gravel frames. Freehub options include Shimano/SRAM 9-11 speed and SRAM XD-R, covering both current drivetrain standards.

At 1,550 grams for the pair, the ATRx 650b is a genuinely lightweight carbon disc wheelset for the format. Both wheels run 24 spokes, a spoke count that balances lateral stiffness and weight while keeping the build serviceable in the field. The 650b format itself is a deliberate choice: a 650b rim running a 47mm tire produces roughly the same total wheel diameter as a 700c running a 28-30mm tire, which means the ATRx fits into frame clearances that suit larger rubber without requiring a 700c-plus build. For gravel frames with generous tire clearance and riders who want maximum traction and compliance from their tires, the 650b platform delivers that without the handling compromise of going to an oversize 700c tire.