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What is the difference between "shocks" and "struts," and what is a "damper" and a "coilover?"

It is a major pet peeve of ours. Customer calls and says they need to replace their shocks and struts. Or just their struts. This wouldn't be so bad but invariably the car they are calling about (if they are calling Heeltoe it is probably a Honda or Acura) doesn't happen to have any struts at all.

Then you've got companies like TEIN making replacements for these units they call "dampers?" And then some homie in the forums is telling you to forget it, and you need to buy "coilovers." Huh?

What is a shock? What is a strut? What is a damper???

Shocks and struts are both types of dampers (do you say damper or dampener?) A damper is basically an absorber. Obviously the springs hold the weight of the car up, and allow the suspension to move as the car goes over bumps and things. Without springs, the car would not be compliant at all. However springs will keep springing long after you want them to stop, so there needs to be something keep them in check. If you hit a spring it would "sproing" and shake and bounce around for a while before it comes to a rest. It is called vibration or oscillation. This is no good in a car because that means the car would bounce around up and down over the slightest of bumps and you'd have little or no control.

While the spring adds compliance, dampers bring control.

Dampers (shocks and struts) keep the springs in check by allowing them only to be as springy as they need to be to provide comfort, but not so springy as to allow the car to float around and feel as though it were not connected to the ground. But really, all you really need to grab on to is the damper controls the ride, the handling, the body motion, and the response of the suspension to road inputs. A system is "under-dampened" when the damper is too weak to keep the mass of the car from bouncing around on the springs (like a Caddy). A system is "over-dampened" when the dampers are very firm and resist movement of the body, even with a softer spring in place. Some movement is needed for the suspension to work properly, or the car will slide over instead of grip the road. What you are shooting for is "critical dampening," which is when the damper is tuned to match the spring and the mass in such a way that any given input results in the car returning to it's neutral position on the spring as fast as possible without oscillating.

But now, on to the rear question: If shocks and struts are both dampers, what is the difference?

The difference between a shock and a strut is in their mounting. To understand the difference you need to "zoom out" and think of the whole suspension system.

The wheel is connected to the hub, which rides on a bearing, which is housed in a hub carrier (also known as a knuckle or an upright). The hub carrier is also the thing that the brake calipers bolt to. The hub carrier can be held to the car in a few different ways, and herein lies the difference between a shock and a strut.

A Subaru WRX has a strut. This is a front strut in a WRX (that's a Tein FLEX damper):

What is it missing in the above picture that this TSX with a shock configuration has?

If you said UPPER CONTROL ARM, you get a gold star!

The simplest way to think of it is that if you were to take the shock out of a car, the wheel would still keep the same geometry and alignment as with it in, because the hub carrier is not located by the shock; it is located with arms. There can be two, three, or even five arms holding the hub carrier in place. But the shock is not one of the things doing that job. It doesn't move other than to compress and rebound over bumps. The mounts are rigid and the only compliance from bushings is there to provide comfort.

By contrast, if you were to take the strut out of the WRX in that pic above, the hub carrier would not be located. It would flop around and not be able to hold a wheel straight. The strut serves as both the damper AND a suspension member. It turns with the steering, so there is usually a bearing in the upper mount to allow it to spin to allow that movement.

Shock = damper. Strut = damper + suspension member.

This should help explain why you won't ever see Skunk2 making camber-adjustable front upper arms for RSXs and Civics newer than 2001; they all have struts. And it should also explain why the upper mounts in TSXs and TLs will never have camber adjustment; moving the location of the shock mounting won't change the alignment because you need an adjustable upper arm for that.

So, know the difference, and when talking about your car say the right thing. When someone says it wrong, you can either correct them or find someone else who is more well versed to talk to.

Hopefully that clears things up a bit, and we've held on to you thus far. Now, what is a "coilover?"

Coilover is really a term that is short for "coil-over shock" or "coil-over strut." The damper in the suspension system need not be all in one assembly like most of our customers see it. Many trucks have leaf springs in the back, and a separate shock. Likewise, the 1984-87 CRXs and Civics that Heeltoe caters to have struts in the front with a torsion bar for the spring.

The damper above is a strut because there is no upper arm, but also notice there is no coil spring! This is not a coil-over strut. Also you'll see a lot of cars where the rear suspension has a trailing arm and the shock is mounted separately from a coil spring, such as on the later RL or later model Civics.

Coil-over literally means there is a coil spring and the coil is over the damper.

A stock TSX a coil-over shock suspension design.

But "coil-over" and "coilovers" are different. These days it is common that an adjustable-height suspension, one where there is a threaded spring mounting, to be called a coilover suspension. It is really nothing more than a damper and a spring, but you can adjust the height.

Aside from a pretty color, coilovers are typically shorter in overall length allowing adequate shock stroke when the car is set to lower ride heights. They usually come have all kinds of features such as adjustable ride-firmness and new upper mounts (and if you have a strut-type car, you'll probably get camber adjstment on those upper mounts).

So, hope that clears things up for you!

About the Author

Marcus di Sabella Marcus is the founder of Heeltoe Automotive. He's been working with cars (mostly Honda cars) since 1996, and has been providing enthusiasts with excellent products, services, and web experiences since 2002. He's been published in Honda Tuning, and holds a degree in Engineering Technology.


1988 honda civic
11-17-2016 08:31 AM at 8:31 AM
So would a 1987 Honda civic have struts in the front and shocks in the rear?
Administrator Note:
Struts in the front, and I believe technically struts in the rear as well. If you remove the rear dampers the entire rear end falls out of the car. There are no upper links at all.
Mohan Yeola
04-19-2016 02:45 AM at 2:45 AM
Wonderful information
Administrator Note:
We do our best!
04-05-2016 11:24 PM at 11:24 PM
This was a very clear article. Thank you.
Administrator Note:
You are welcome!
give all type of images with names
06-29-2015 02:26 AM at 2:26 AM
i would like to see all type of damper & shock absorber
Administrator Note:
We'd love to give more info. We feel we have explained the difference between a shock and a strut (the only two kinds of dampers you'll find on a motor vehicle) and how they are both "dampers." Do you have a particular question that you are not sure about? We are not sure what other types of dampers you are referring to.
Great explanation for me.
05-17-2015 09:45 PM at 9:45 PM
Great explanation for me. I was thoroughly confused.

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