The AR40 is the latest addition to the Foundation lineup. Featuring an aerodynamically optimized 40mm rim depth front and rear with a 25mm internal rim width, the AR40 is designed to deliver ultimate versatility for the road rider and racer looking for performance on and off-road. Borrowing from ENVE's SES rim design knowledge, the AR40 is aerodynamically tuned for 29–30mm tires and delivers drag reduction that punches above its depth and price point. Wind tunnel tested at the Mercedes-Benz Formula One Wind Tunnel and validated at real-world speeds, the AR40 brings best-in-class aerodynamics to the Foundation customer — at a price that doesn't compromise. Built on the ENVE INNERDRIVE Foundation hub, the AR40 features an oversized 42mm ratchet drive system positioned inboard over the bearings for reduced axle stress, longer bearing life, and reliable engagement. Patented Molded Spoke Hole technology routes carbon fibers around each spoke hole — never cutting them — resulting in a lighter, stronger rim capable of sustaining higher spoke tensions with minimal maintenance. While designed primarily for on-road performance, the AR40 has been tested and qualified to ENVE's gravel standards, making it a true do-it-all upgrade for modern road, all-road, and gravel racing bikes. Ultimate versatility for the on and off-road rider 1515g Wheelset Weight Avg. (±3%) Internal Rim Width: 25mm Aero optimized tire size: 29–30mm Tested and qualified to ENVE's gravel standards Wide Hookless Bead for pothole and impact protection ENVE INNERDRIVE Foundation Hub with 42mm ratchet drive system For use with tubeless tires only — tire must be listed as "Approved/Recommended" on ENVE's Tire Compatibility Page Available in HG and XDR freehub configurations. Front wheel MSRP $630 USD | Rear wheel MSRP $770 USD.