Bicycle wheel how well the wheel transmits propulsive and braking forces, if applied at the hub, as in the case of hub or disc brakes. Several factors affect these stiffnesses to varying degrees. These include wheel radius, rim bending and torsional stiffness, number of spokes, spoke gauge, lacing pattern, hub stiffness, hub flange spacing, hub radius. In general lateral and radial stiffness decreases with the number of spoke crossings and torsional stiffness increases with the number of spoke crossings. One factor that has little influence on these stiffnesses is spoke tension. Too much spoke tension, however, can lead to catastrophic failure in
Tire Wear bars (or wear indicators) are raised features located at the bottom of the tread grooves that indicate the tire has reached its wear limit. When the tread lugs are worn to the point that the wear bars connect across the lugs, the tires are fully worn and should be taken out of service. Most wear bars indicate a remaining tread depth of and are tires are deemed "worn out" when the tread is worn down to that point. The tire bead is the part of the tire that contacts the rim on the wheel. The bead is typically reinforced