Struts vs. shocks


#1

We just gave some advice to someone in the “repair & maintenance” section about changing struts, and I was just reminiscing about the old days with double A-frames and shocks. Shocks were so easy and inexpensive to change before MacPherson struts became common. I understand that struts free more underhood real estate to allow transverse motors to get stuffed in, and I’m sure they reduce manufacturing costs, but I miss shocks. Sigh. {:slight_smile:


#2

These days so much has been added to shocks they cost as much as struts. Spring seats and fork arms to go around driveshafts plus the rebound and bump stops in the shock all add a bunch of costs.

In the old days none of that, except a solid rebound stop, was in the shocks.


#3

Point made.
But standard shocks for RWD vehicles, even with fancier valving, are still a fraction of the cost of struts, and the bumpers used to be big rubber blocks mounted on the A-frame (or its mount). And they were SOOO easy to change. :smile:
It typically costs about $600 or so per car’s end to get new struts, it costs less than $100 for a pair of basic OEM-replacement shocks from a reputable manufacturer… and I can change them in my driveway and don’t need an alignment after!


#4

Well, my now gone Mazda CX-9 had rear shocks, but the problem was that to get to the top bolt on the shocks you had to take remove the third row seats and bunch of other interior stuff to get to the bolt; easy enough !!


#5

Yep, used to be able to do all four in an afternoon and a little over $100, and didn’t risk your life doing it.


#6

Do you miss king pins and I-beams too? :smile:

Both have advantages. A McPherson setup eliminates one control arm and bushings, those upper A-arm bushings used to be a pretty decent wear item and cost a little bit to replace.

And try to replace the rear shocks on a Crown Victoria/Grand Marquis/Town Car in your driveway. You’ll be wishing they were struts.


#7

“Do you miss king pins and I-beams too?”

Not one bit.


#8

A good friend of mine, and a long time damper engineer, coined a phrase; Struts are a telescopic structural device Think about that for a moment… :wink:

The company I used to work for made a bunch of money making struts because they did so much more and we had more content. We used to build what we called a “strut module” which was the entire strut-spring-mount assembly built to the assembly schedule with the correct strut, spring and mount for the specific car coming down the line. Saved a bunch of assembly labor at the plant.

Different option groups needed heavier springs or dampers or softer mounts. One carline had left/right mounts, 3 different struts, 6(3 right - 3 left) different mounts and 15 different springs that all had to be properly assembled. So figure at least 90 final assembly part numbers just for the Chevy. And another 90 for the Pontiac version of the same car. Then there is Buick and Olds as well for the old X-cars.

And the manufacturing engineers used to complain to us when one car took 3 different rear shocks with the only difference being internal valve springs.


#9

Do I miss kingpins and I beams too? Nope. There’s a lot of things I don’t miss. But they have absolutely zero to do with my post. And yup, there was an occasional car with shocks that were a challenge to change. But my post was never intended to be all-encompassing.

Mustangman, I like that description… a lot. A lot of people have the mistaken perception that struts are the same as shocks, and I’ve always found it hard to concisely point out that isn’t so. If I had a better memory I just might use your friend’s description. :smiley:


#10

Many non-car guys think a McPherson strut is a Scottish dance!


#11

Needing new front struts necessitating an alignment, I miss shocks. It is not a job on an 03 trailblazer I wish to tackle. $500 oh well.


#12

My personal preference is for struts although I’m in full agreement that (in most cases anyway) it does run the amount of time ($) up required to change them.

Not all regular shocks are cheap though. The rear shock grommets were getting beat up on my Lincoln Mark and finding regular rear shocks for that car is difficult and expensive. I finally found a pair at 125 each (ouch) and opted to go another route based on price alone.

Some fishing around about overall length, travel, and so on led me to use a pair of shocks for a '71 Lincoln Mark. About 35 bucks for the pair and that was more palatable.


#13

In my own car the shocks are set up so similar to struts, with the coils around them getting squeezed by coil mounts just like struts, that it’d be easy to confuse them with struts. The only real difference is that the dynamics of the wheel are controlled by upper & lower control arms rather than the damper itself, and it has a regular shock mount on the bottom instead of the two beefy bolts bolting it to a knuckle. But since it still requires removal of the assembly, squishing of the spring and removal of it from the damper, and new spring mounts, upper mount, etc., it’s almost as labor intensive as a strut… but without the need for an alignment. Clearly every effort was made to reduce manufacturing costs. Can’t complain, because if it had been done the old fashioned way, such that the shock could be removed separate from the spring, the cost of the car would have been higher.

Here’s a sketch.


#14

I miss shocks also. Mainly since they were easy money.
Depending on the car one could swap out all four in 15 minutes.
Others…not so much.


#15

Docnick
Many non-car guys think a McPherson strut is a Scottish dance!

I had a McPherson strut one time. Alka Seltzer works great for that!


#16

@Barkydog, I hate to break it to you, but your 03 Trailblazer has shocks on all 4 corners! The front shocks are those expensive, lots-of-added-features, shocks I mentioned in an earlier post.

The need for alignment is either because the springs are being changed, the upper A-arm needs to be removed to get the shock out or the mechanic has a boat payment due…


#17

Or the tire wear suggests that it would be a good idea…
I’m generally against unnecessary work, but I’m not against an alignment after replacing chassis components, including shocks. I realize opinions may vary.


#18
Many non-car guys think a McPherson strut is a Scottish dance!
Seem to remember Elle McPherson "strutting" in SI during my formative years...

#19

Called a dealer for a quote $200 more including alignment, from reading on trailvoy it seems sometimes difficulty is trying to separate the shock from the spring, so they do the whole deal, and new springs can affect camber. Still learning, thanks @Mustangman


#20

On a serious note, what’s the difference between a strut and coil-over shocks? I thought that was the definition of a strut–the shock and the spring are integral to each other–but apparently, you can have that packaging and still not be a strut.