Built for reliability on every mountain bike (MTB) ride, this trail-ready rim features a 28mm wide asymmetric rim shape and ultra-strong 6069 alloy to handle the demands of modern MTB riding. Mountain bikes have changed in the decade since the original Arch rim helped introduce the world to tubeless technology. Today’s Arch MK4 rim has evolved to match these more capable bikes. Through all the years of testing and refinement of this rim, one thing has never changed: versatility. Now more than ever, when you want a reliable rim that can handle every trail, the Arch MK4 is for you. 6069 Aluminium Alloy Rim The Arch MK4 rim is light enough to take XC racing but was born from research and testing on the Enduro World Series circuit, making it a great rim for anyone looking to improve both descending and climbing. Constructed of light and strong 6069 aluminium alloy, with a reinforced spoke bed and 28mm internal width ideal for 2.2-2.5″ tyres, the Arch MK4 can get you up the climbs easier and make the descent even better. Asymmetric Shape The Arch MK4’s BST Asymmetric shape improves spoke angle, allowing for a stronger overall wheel build. Unlike most asymmetric rims that struggle with tubeless inflation and consistent airtight seal under hard cornering, the Arch MK4’s shape is designed to equalize pressure for easy inflation and incredibly strong tyre retention on both sides of the rim. Patented Bead Socket Technology Stan’s patented Bead Socket Technology, combined with a stronger asymmetric design, light and durable 6069 alloy, and the perfect rim width for balancing control and weight, make the Arch MK4 your best choice for all-around riding. Powering up rocky switchback climbs or slapping berms on every descent, the Arch MK4 is ready for whatever you can throw at it.   Additional Item Top Features: ETRTO: 26" Option: 559x28.0; 27.5" Option: 584x28.0; 29" Option: 622x28.0 ERD: 26" Option: 536mm, 2.5mm Offset mm; 27.5" Option: 561mm, 2.5mm Offset mm; 29" Option: 600mm, 2.5mm Offset Max Spoke Tension: 130kgf (1275N) Max Pressure with 2.20" Tyre: 41psi Max Pressure with 2.50" Tyre: 35psi   Technologies: - Versatile 28mm internal rim width optimized for 2.2-2.5” tyres. - Light and durable 6069 aluminium with welded joint and reinforced spoke bed. - BST Asymmetric design combines Stan’s legendary easy tubeless inflation with a stronger, more balanced wheel build. - 3-year rim warranty with 1-year crash replacement.