A car that bounces as you go down the road can be very tiring and very annoying. And keeping it from bouncing is the job of the shock absorbers and or the struts. Whichever your car happens to have. Now the way you test them is, a couple times a year, you go around each corner of the car and bounce it up and down, like I did this one. And what's going to happen is, it's going to go like this. You let go of it in the down position, and if the shock or strut on that corner of the car is good, it'll come back to the center and it will stop. It won't continue to bounce. If it continues to bounce, probably you need new shocks or struts.

But what's the difference between a shock absorber and strut? Well here we have an example of a strut. Now, what this does is, it has a shock absorber in the middle, and then around it it has a spring to support the weight of the vehicle. A shock absorber on the other hand, such as we have here, these shocks do not have the springs on them. They have nothing to do with the height of the vehicle or anything like that. The only thing they do is to keep the car from bouncing. The spring is mounted someplace away from the shock.

Now, a shock or a strut, whichever it is, all they do is convert the vertical movement of the car into heat energy, they damped it, so that you don't go down the road just kind of, a motorboat effect, just floating along. Now if you have bad shocks or struts, and they can wear out in as little as fifty thousand miles, or it may be a hundred and fifty thousand. But you should cheek them two or three times a year. And when they're bad, replace them in pairs. Two fronts or two rears.

Now, here's the thing. This shock, right here, this one is worn out. If we push this down, we see that it comes back virtually immediately. Now over here we have a brand new one. This gives you an idea as to what these things do. As you see, this comes back very slowly. It's very controlled, and that's how it controls the ride of your vehicle. So, check them on a regular basis, replace in pairs when necessary, and remember that if you don't replace them, you can have a dangerous car, that's number one. But number two, you could have severe tire wear problems, as the result of a bad shock or strut. And if you have a question or comment, drop me a line. Right here, at MotorWeek.