Thread: Coaxial Spring Mounts for Shocks (Not Struts)?

Reading one of the Autocross to Win articles the writer mentions the importance of coaxial spring mounts, where the spring is mounted on the shock shaft and not on the top hat.



For our cars what I noticed is, the struts get coaxial spring mounts, but shocks get the shaft and are mounted on the top hat itself.

Here are BC struts for the B15

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Exploded view


Rear's are shocks and are mounted on the top hat.



Here are front BC shocks for the P11, once again mounted on the top hat.



I'm using BC's as an example because I have pics more readily available, even other brands I'm seeing the same trends. If car has struts in the rear, then the spring is mounted on the shaft (P10/B13), if car has shocks then spring seems to be mounted on the top hat. Do our cars with shocks not experience the items that the article talks about, thus it's not needed?

The author writes around DSM chassis, which afaik has some sort of unequal a arm suspension (not McStrut), but he does mention that in their design shock still moves.

I think it might be the whole strut vs shock. Since shocks are designed to only dampen the springs, they do not experience the same loads that a strut would. Thus there is no sideways loads to distort the spring, it still seems weird that a double wishbone car like a Talon would have strut like properties.

The Pic from Far North racing is for struts and that is how mine are setup F/R of the B13. For the P11, all the articulation/motion comes in the multi-link and the shock/spring isn't part of the equation.

Brent

Well that's why I was curious about it, it makes senses for McStruts but not for other suspension designs. His car doesn't seem to have a McPherson setup, but I guess it could still be using struts even in a double wishbone config (weird?).

This is a good point, i always wondered about this as well. I made some offset top hats with spherical bearings and when I install them the coilovers just hang straight down and I have to pull it slightly to mount the bottom to the 3rd member. Which tells me right away that the spring is at an angle to the top hat and not square.

I did not have this problem when the top hat was centred and not offset. So maybe ppl with offset mounts should look into this.
I know I am, I may build a set and see how it goes although it will take away from shock travel slightly.
my current setup: