I am not a mechanic. However, I have been driving cars for more than 30 years and have been around a shop once or twice. Recently, an Atlanta mother died when a motorist’s wheel (rim and all) allegedly came off his vehicle and crushed the roof of the mother’s vehicle causing instant death.
Most motorists don’t pay attention to their tires unless they see a little yellow light on their dashboard alerting them to low pressure. I believe the same conclusion applies to motorists who actually rotate (front to the back and back to the front) their tires. But – I digress.
The question is how does a wheel disengage from a moving vehicle. Let’s start by covering the bases of how a tire might blow or rip from the rim. If a tire is underinflated, then the tire has more surface area flat on the road surface while still keeping the chassis suspended on four wheels. In this situation, the tire can flex beyond its elastic limit and overheat and blowout. By contrast, an overinflated tire combined with longstanding tire wear or a poor retread could lead to a blowout. When a tire is overinflated, the tire tread does not adequately grip the road as less tire tread lies flat on the road. Over time, an overinflated tire can lead to a blow out. Yet, these situations don’t account for a complete wheel and rim coming off a moving vehicle.
Here are the basics. A tire is fit around a metal rim. Between the rim and the tire is oxygen or nitrogen that helps fit and secures the tire to the rim. The metal rim is secured to the car by several lug nuts. Additionally, some older vehicles have wheel ball bearings (steel bars held together by a metal ring) that need to be replaced or re-greased over the lifetime of the vehicle. Newer model vehicles have ball bearings that are sealed and do not need any maintenance. The wheel bearings (set of ball bearings) help support the wheel and ride on the axle shaft. The wheel bearing is located at the hub in the center of the wheel. The hub is located where the lug bolts come through the wheel.
Continue Reading