The Flow MK4 wheelset lets you do more. Since 2007, there's a reason the best riders in the world have come to us to ask for Flows. Corner harder, send it further, and carry more speed through any section of trail. Today's Flow MK4 gives you the control you need to push boundaries. The Flow MK4 rim's patented BST Asymmetric shape creates the most reliable tubeless seal.The rim's durable 6069 alloy construction and reinforced spoke bed, combined with the offset drilling of the asym design, builds into an incredibly durable wheel that brings added confidence to every ride. Strength and serviceability are long-standing priorities of every Stan’s wheel, and the Flow MK4 wheel takes those priorities further than ever before. The asym rim design allows for a single spoke length to be used on both the front and rear wheels. As with all Stan’s wheels, traditional J-bend spokes and lacing are used for their proven strength, ride quality, and serviceability. Available with Shimano Micro Spline, HG, or SRAM XDR freehubs, with options to fit all popular axle configurations. Tubeless ready with rim tape installed. Wide, light, strong, and tubeless, the original Flow redefined what a mountain bike rim could do.Today's Flow MK4 wheelset gives you the confidence to do even more. M-PULSE HUBS The M-pulse hubs at the heart of Flow MK4 wheels combine an absolutely bombproof magnetic locking engagement with incredibly smooth rolling. Based on the original innovative Project321 engagement system, the speed and durability of this system is unmatched. Unlike weaker pawl and spring designs, the M-pulse features six pawls with Neodymium magnets that offer virtually no resistance when coasting, but lock the pawl teeth into place far more reliably and consistently than springs. Each detail of the M-pulse hub was engineered to systematically eliminate weaknesses found in other designs. The 17mm axles are made of 7075 aluminum and roll on Enduro brand bearings, including a double-row freehub bearing tested to be far more durable than two individual separate bearings. The entire hub is also shielded, meaning no bearing seal is visible, offering superior protection for all conditions. With only 1.66°of rotating required for the M-pulse hub to engage, power is always instantaneous. Multiple tooth engagement provides a greater surface area to distribute load to improve both durability and speed. The angle of the pawls was even optimized to distribute stress away from the rotating bearings. Beyond the strength and speed of engagement, M-pulse hubs feature adjustable preload, allowing a tremendous decrease in drag for less resistance and more speed. Low-profile 30mm internal width optimizes tire shape,traction, and control for 2.3-2.6” tires Durable 6069 aluminum with welded joint and reinforced spoke bed BST Asymmetric design combines Stan’s legendary easy tubeless inflation with a stronger, more balanced wheel build New high-end premium M-Pulse hub with 216 points of engagement (1.66º), magnetic-sprung pawls to reduce drag and improve response, Enduro bearings and external preload adjustment. US-made internals in partnership with Project321 Matched wheelsets use traditional J-bend lacing and share a single spoke length for easy serviceability SPECIFICATIONS RIM INTERNAL WIDTH: 30.0mm RIM EXTRENAL WIDTH: 33.6mm RIM DEPTH: 18.9mm SPOKES: Sapim D-Light, 2.0/1.65/2.0 NIPPLES: Sapim Double Square Alloy Black HUB: M-pulse DRILLING: 32-hole RIM MATERIAL: 6069 Aluminum Alloy WEIGHT: 1882g