Springs, Shackles, and Shocks

[illzoni]

My core question is about suspensions in general...
Does the vehicle's weight ride on the springs, the shocks, or a combination?

Background...
I'd previously posted about lowering the rear of my '87 4Runner, as it has 63" Chevy springs and 6" shackles:
http://www.toyota-4runner.org/classic-t4rs/67130-no-more-stinkbug-lowered-my-rear-end.html
and
1987 Toyota 4Runner

More recently I'd asked for urgent assistance with the rear shock mount nut size and posted some lessons:
http://www.toyota-4runner.org/classic-t4rs/77322-urgent-need-bolt-size-rear-shock-mount-1987-a.html

When I was remounting my shocks, I found the rear ride height changed pretty significantly. With the truck resting on the springs alone (no shocks) my rear bumper was just over 26" off the ground. After reinstalling the shocks the bumper is over 28" off the ground. That indicates to me the weight of the truck is largely resting on the shocks. My understanding of suspension is the weight should rest on the spings, with the shocks simply controlling the weight's movement. Am I close to correct?

My guess is I've contributed to this 'problem' by lowering the rear end via shorter shackles (as described in linked thread above; changed shackle from 6" to 3"). Should I reverse this and put the shackle distance back to 6" and thus remove some load from the shocks?

Thx,
Jon

 

[illzoni]

Wow, I'm getting plenty of views, but no comments.

Does anyone have any advice?

 

[Vantage85]

I noticed a similar issue with my old '02 Tacoma.

I had a set of deaver leafs approx 3" lift when paired with 8" stroke bilstien shocks.

When I installed a longer set of 10" shocks, I noticed the rear was about 3/4" taller.

I believe this was because of stiffer valving in the shock, and the fact the the shock was now more compressed (by an inch in my case) compared to a shorter version. So more resistance was met in the shock itself.


That being said, I could still fully flex and compress the shock when wheeling, and apart from a little stiffer ride (valving) and more rake i barely noticed.

 

[fourwd1]

My core question is about suspensions in general...
Does the vehicle's weight ride on the springs, the shocks, or a combination?

Jon

The vehicle rides on the springs (except for some speciality shocks like air shocks).
Shocks are dampers, they control suspension rebound to make a smoother ride.

Now if the shocks are too stiff or sized incorrectly for the application, they could possibly prevent the suspension from settling down properly (which kind of what you describe).

 

[illzoni]

Hmmm....

Maybe I should put the shackles back in the 6" position, take a measurement, then disconnect the shocks, and measure again to compare.