Strut Your Stuff

A friend mentioned the other day that her boyfriend's car was suffering from a broken strut (and another on the way out), and I said, "Oh, no, that's awful.  That's a pretty major repair."  And it is-- I mean, I've heard the Car Talk guys mention it in hushed tones a few times.  But then I thought (to myself, so I wouldn't look like a moron), well, I know that a strut is a structural component. It's a support, right?  It resists stress of some sort.  That's what a strut in general is, anyway.  But what exactly is an automotive strut?

To the Internet!  FOR JUSTICE!  Ahem.

One of the most common automotive struts is the MacPherson strut, which really does sound like a dance move of some sort, but oh well.  The MacPherson strut is indeed a supporting structure, but more specifically it's part of the suspension, to wit: those elements of the car that keep it more or less level as it bounces in and out of the inevitable potholes.  I don't want to even think about what the neighborhood around the office is going to look like at the end of the winter, especially since the recent storm probably bankrupted the city.  But I digress.  Again.

The Wikipedia article suffers from a lot of technical language, and seems to be written so that only people who already know the material can follow the text, but I'll try to give some of the high points.

The "main" part of the strut is attached to the center of the wheel and extends upward into a spring, which is connected in turn to the main body of the automobile.  It looks a little bit like the shocks on a mountain bike, for  fairly obvious reasons.  This element evens out the vertical motion of the wheel, making the ride smoother.  But that's only the vertical.  So the strut also has two horizontal components that link the wheel to the steering mechanism and provide additional stability.  This design offers a combination of ease of manufacture and low cost, at the expense of some ride quality and sophistication.

All of which means that my friend's boyfriend's car is probably wallowing around like a whale with a prosthetic leg.