Sealed cartridge bearings Equally adept on fast, rolling roads or mountain terrain, the Ksyrium Pro UST gives you all the advantages of our Road Tubeless system including less rolling resistance and a smoother ride quality. When paired with the new Yksion Pro UST tubeless tires, you get a perfect union between the wheel and tire, ensuring easy, hassle-free installation and removal thanks to our proven UST technology. And no tubes means no friction with the tire, so you roll faster using less energy. You can also lower your tire pressure for a smoother, more compliant ride, even on rough roads, with a reduced risk of punctures. Beyond the benefits of tubeless, all the other favorite features of this wheel stay the same. A wider rim shape (17mm internally) allows for an 18% increase in air volume for your tires. That extra volume gives you a more controlled and comfortable ride without compromising efficiency. The Zicral alloy spokes are stiffer, stronger and lighter than traditional stainless steel spokes. The Isopulse lacing pattern (radial lacing on the drive side) allows a more balanced spoke tension for a stiffer, more stable wheel. Fore drilling creates the strongest possible connection between rim and spokes, increasing stiffness by about 20%. Each part of the rim is precisely machined using just the right amount of material to provide stiffness and strength, while maintaining weight at only 400g. Total wheel weight is about 1420g.