Most bike tires feature a bead, the raised element around the inside edge that locks the rubber against the rim.
Wider tires are measured in inches according to their bead-to-bead diameter and width, for example 26 x 2.0.
Most adult-sized bikes use 26-inch tires, though 29- inch tires can be found on an increasing number of large-wheeled mountain bikes.
Road bike and other narrow tires are referred to as 700C tires, a measure of their diameter in millimeters; width is also listed in millimeters and ranges from approximately 18 (fast road bikes) to 28 (more stable touring bikes).
Slicks are smooth tires that reduce rolling resistance. Knobbies feature raised elements for increased traction.
Bike tubes use two kinds of valves. Presta valves (pictured) are tall, skinny, and contain high pressure without leaking air. They are common on road bikes. Schrader valves are standard on most other bikes, the same type you’ll find on a car tire. They very slowly leak air, usually over a period of months.
Equipped blogger Matt Heid is AMC's gear guru: He loves gear and he loves using it in the field. While researching several guidebooks, including AMC's Best Backpacking in New England, he has hiked thousands of miles across New England, California, and Alaska, among other wilderness destinations. He also cycles, climbs, and surfs.