mastacox

LOL


I am the triumphant champion of nerdiness...

4Crawler

iTrader: (3)

Well, two conditions to look at with inboarding the shocks, with them mounted vertically. For straight up and down suspension movement (equal on both sides), it makes no difference where the shock is mounted as the whole chassis moves up and down equally relative to the axle.

Only for cases where you have body roll or axle articulation will there be a difference. And then, you'll see two factors at work, both related to the inboarded shocks. Firstly, their leverage on the axle, relative to the wheels will be reduced by their degree of inboarding. But then, just like the angled shock case, the shock will compress slower the more inboard it is mounted, and thus will generate less force.

So you again get into a case where you have less force acting with less leverage so those two effects must be combined, at least for the body roll case. So for a shock mounted 1/2 way between the WMS and center, it has 50% leverage against rolling and will make 50% the force since it compresses only 50% as fast as if it were out farther, so it is 25% as effective as the same shock out at the WMS (which of course is not practical to do).

The "real" effectiveness would lie someplace between the up-down value and the roll value, depending on what mix of suspension travel you wished to test the system with.

mastacox

Oops, missed that. Good catch.

EDIT:

And just for good measure, a graph comparing the qualitative behaviors of angled and inboard shocks. I made the X-axis a ratio, where for the angled shocks the angle is 90deg*Ratio, and for the inboard shocks a distance ratio measured from the WMS divided by the distance from WMS to the center of the axle. Obviously, there is no cross-over optimization in this case...

EDIT AGAIN:

Or if you prefer, a pretty picture comparing the two. "Overall Effectiveness" is defined as (Angled Effectiveness) * (Inboard Effectiveness). Also added a contour plot which is possibly useful for seeing where your shocks sit in terms of overall effectiveness.

dfoxengr

just wanted to say that i do see your view, and it made me think a bit.
i learned a lesson, and am actually seeing how you could be right. foot in the mouth huh, lol.
oh well. on we move.

thanks roger. in the entire system i do believe you are correct assuming velocity doesnt change due to the less force output by the angled shock, thus making it a non-cyclic problem. my professor and i were thinking of the problem as the book posted does.

im difficult to convince sometimes, but thanks for keeping it up.

AxleIke

Well, it is cool that we all learned something.

however, i could care less about that, as we have now 5 pages of thread, and no updates

I would like to see your progress on the vertical 4 shock set up. This sounds pretty cool, and like it can work. I am interested to see your plans, and if you've gotten work done thus far. Pictures are a must.

dfoxengr

actually ill be doing the two fox inboard shocks, and a sway bar in the rear i believe.

will be analyzing it in matlab for my land vehicle dynamics project this semester. will possibly make a thread about it when i get it done over summer.

mastacox

Speaking of over-shocking...

Saw this Toyota Pickup at Truckin' Nationals in Phoenix and wanted to slap the owner:

deathrunner

What The???????

mastacox

LOL, I think I count 17 shocks on the rear axle, and 12 shocks with 4 steering stabilizers on the front... I'm guessing the ride is the same as if he had just welded the axles to the frame

yotarover

\
keep coming up with formulas and a few pics and some say so's here and there. so does mounting them inward at a 45* allow more flex yay or nay? my rear does not seem to flex much.. chevy's are in the process it might as well be as stiff as a dead body

4Crawler

iTrader: (3)

For a given length shock, the more angle the shock is off of vertical, the more travel it will have in a vertical direction. So at 45 degrees, the shock is only extending about 70% of the amount the axle moves. Now whether that equates to more flex depends on what is limiting the flex now. If you were shock-limited before, possibly because of the shock mounts, then yes, angling those same shocks inward would give more flex, assuming the springs will accommodate that added travel:
- http://www.4crawler.com/4x4/4R_suspe...tml#ShockAngle

I know with the factory rear shock mounts on the frame and lower spring plate, you are really limited by having a shock with a short enough compressed length to allow the springs to compress the bump stops and that then limits how far that same shock can extend.

yotarover

thanks Roger,

gary_the_4runner

127 shocks and still using push pull steering??


all of this banter and do we have an ULTIMATE result of ideal placement of shocks? or should i just mount the sky mfg rear shock hoop where ever i want to?

sebastianholmes

lol thats what the 3 front to back horizintal shocks on the front are for!


this thread gave me a headache lol im only in highschool but i am planning on being a mechanical engineer of some sort

Mountain Cop

Holy old thread revival!

I started this thread feeling entertained. I even felt like I understood what was going on at first. Then... I began to see numbers and symbols and odd equations, and I began to feel very very stupid. The interesting thing is, I actually read through the thread and with what high school math I still retain, I sort of understand it. I now feel smarter, mostly due to some VERY well thought out and explained arguments. I also have a certain amount of respect for the OP, who was man enough to admit his mistakes.

In short, it moved me.

4Crawler

iTrader: (3)

No real ultimate placement rule. More vertical makes a more effective shock, angled over more gives more travel from a given length shock. So it all depends on what your goals are and what shocks, mounts and suspension setup you have. If you have a truggy and can mount the shocks anyplace you want (and as high as you want), then you can put in a long enough shock to work fully vertical. But if you are stuck with shocks mounted below the body/bed, then it is unlikely you can fit a long enough shock underneath there straight up and down. So angle inward until you can. That is why I made my upper shock mount with 6 mounting points/side:



And over the years, I have used almost all those points as I fine tuned the setup.

dfoxengr

wow...the OP is an A-hole, lol... ahh so much learned since then. mostly complete research before speaking.

I did go ahead and do the two vertical fox shocks spaced at about 75% of track. they are vertically mounted. ride is pretty rough and I am now considering leaning them in about 15-20* for a bit less damping.

GonOvr

I bet if all those shocks were charged he could take the springs off and it wouldnt drop. WTF over.