Mechanically Speaking

Mechanically Speaking

Mechanically Speaking: Why is there a whole lotta shakin goin on?

"When your steering wheel is shaking in your hands while you are driving it is not good."

There is nothing I hate worse than heading out on a road trip and then realizing when I get up to highway speed my vehicle starts to shake. The winter season is typically the worst for this. The shake may be only slight or it may be severe. In all cases a shake is bad. Bad for you and bad for your car.

When your steering wheel is shaking in your hands while you are driving it is not good. When you are feeling a constant rumble through the seat of your pants it is not good. What feels bad to you is bad for many of the components in your vehicle, especially steering and suspension components. It will accelerate their wear. It may also loosen your fillings.

There are lots of reasons that your ride is not as smooth as you remember in the fall when you last serviced your vehicle and installed your winter tires. Winter driving can take its toll on your vehicle.

Before you start thinking the worst and fearing the cost of repairs I will let you in on a little secret. The repair for a winter shake is likely simple. It is the result of uneven built up mud, snow, and ice in your wheels.

Winter driving on snowy, sanded and salted roads causes a sort of caked on even deposit inside your wheels. The buildup applies itself very evenly around the inside of the wheels as the wheels rotate. As long as this buildup remains even it will not upset the tire and wheel balance.

There are a few scenarios that will easily upset the balance. One of the most common is caused by the owner unknowingly. With good intentions on an above zero day you head to the car wash. While hosing the wheels especially wheels with large openings the water will wash off only patches of that evenly spread buildup on the inside of the wheels. What you end up doing is similar to unbalancing your wheels. To avoid this problem you have to be super diligent with the hose. Every stitch of buildup must be removed to keep your wheels balanced and running smoothly.

In some cases it will be too difficult to get all the mud, etc. removed without removing the wheels from the car and physically cleaning them out.

Sometimes a simple freeze thaw will cause the exact same problem. The last snowfall you drove in may have built up an even layer of ice, snow and sand inside the wheels. Then you park your vehicle in a warm garage or maybe in the sun the next day. Gravity and above zero temperatures means that the snow, ice, and sand conglomerate at the top of the inside of the wheel. It then melts and drops onto the bottom side of the wheel where it again freezes when the temperature cools down again.

When this happens the shake you get is typically very severe. Again repair is likely just a remove and clean out the dirt.

Another similar case can happen just from a sharp bump. Maybe you hit a pretty good pothole. Maybe you bump a curb a little hard. Again a piece of build up drops off and essentially destroys your wheel balance.

Not all shakes are the result of wheel balance but many are and a simple inside wheel cleaning will get your vehicle back to smooth sailing.

Trail’s Ron Nutini is a licensed automotive technician and graduate of mechanical engineering from UBC. E-mail: nutechauto@telus.net

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