Here are some characteristics of a tire rim to keep in mind when purchasing wheel and tire packages or rims and tires in general:
- Diameter: distance between the intersection of the bead seats and the vertical walls of the rim flanges.
- Width: distance between the rim flanges.
- Type: Depends on the type of vehicle and tire. There are various rim profiles, as well as the number of rim components. Modern passenger vehicles and tubeless tires typically use one-piece rims with a “safety” rim profile. The safety feature helps keep the tire bead held to the rim under adverse conditions by having a pair of safety humps extending inwardly of the rim toward the other tire bead seat from an outer contoured surface of the rim.Heavy vehicles and some trucks may have a removable multi-piece rim assembly consisting of a base that mounts to the wheel and axle. They then have either a side ring or a side and lock ring combination. These parts are removable from one side for tire mounting, while the opposite side attached to the base has a fixed flange.
- Vehicle performance: Because the rim is where the tire resides on the wheel and the rim supports the tire shape, the dimensions of the rims are a factor in the handling characteristics of an automobile. For example: Overly wide rims in relation to the tire width for a particular car may result in more vibration and less comfortable ride because the sidewalls of the tire have insufficient curvature to flex properly over rough driving surfaces. Oversized rims will cause the tire to rub when turning.Overly narrow rims in relation to the tire width may cause poor handling as the tire may distort sideways under fast cornering. On motorcycles, a narrow rim will alter the tire profile, concentrating tire wear in a very small area during cornering, with a smaller contact patch during braking.