Tubeless-ready rims are compatible with both standard and tubeless-ready tires. When a tubeless-ready tire is mounted on a tubeless-ready rim with special tubeless rim tape, valve, and sealant, the tire and rim form an airtight chamber that no longer requires a tube. This lets you run lower tire pressure with less fear of pinch flats and without the added weight of a tube. Lower tire pressure has many benefits, including greater traction and lower rolling resistance over rough surfaces. The rim can always be used with a tube, as well, by simply removing the tubeless valve stem and installing a standard tube like you would with any non-tubeless tire.