Ignore your car’s noises at your peril
No matter how much you like your vehicle, an unwanted vibration can turn that love affair sour faster than a Formula One lap time. Like certain annoying noises, vibrations can be much more than a negative distraction — they can be symptoms of something gone wrong. And sometimes, if left unattended, they can lead to expensive failures.
Tires are the No. 1 cause of vehicle vibrations. While they can occur at any speed, a typical out-of-balance or otherwise defective tire and wheel will display higher-frequency vibrations at speeds over 60 kilometres an hour. If you can drive “through” the shakes by increasing or decreasing speed, you’re likely dealing with a tire vibration.
This type of vibration may often be resolved by rebalancing the unit, but not always. Wheels can bend from impacts and tires can even become less round for the same reason. In addition, wheel hubs can cause vibrations if any rust or stuck-on grit prevents the wheel properly seating. This can often be rectified with a wire brush.
Basic tire-balancing equipment, no matter how expensive or advanced, can’t solve all tire vibrations. This is why many high-volume tire specialty shops and OEM dealerships have invested in roadforce balancing equipment. These balancers use a roller that applies force to the tire’s tread-face while it’s spinning to simulate loads when rolling down the road. In rare cases, where regular balancing doesn’t resolve a vibration, and there are no problems with the tire or wheel, road-force balancing will usually do the trick — albeit at a slightly higher cost.
Interestingly enough, strobe-light balancers — an older technology that’s now very hard to find — can actually provide a better result. These were commonly used several decades ago and didn’t require the wheel and tire to be removed from the vehicle. When wheels were balanced using this method, it took into account and balanced the wheel hub assembly as well, providing a more accurate result.
Beyond tires, driveline vibrations are most often caused by driveshafts and mainly affect trucks and SUVs because of their longer driveshafts leading to the rear axle. Often when a joint of these shafts starts to seize, it will cause the shaft to spin out of balance. These vibrations often start as being only noticeable during acceleration or deceleration.
Driveshaft vibrations can be an early warning sign of impending failure. If you leave one unattended long enough, the joint causing the shakes can fail, completely dropping the shaft to the ground and leaving you stranded.
If you’ve ever crawled underneath your truck and taken a good look at its driveshaft, you’ll notice small pieces of metal tack-welded onto its surface. These are balance weights, and driveshaft balancing is a specialty. The equipment and skill sets needed are usually only found at heavy-truck repair centres.