Suspension travel upgrades on an 80

[Walking Eagle]

Ok WE
I didn't realize that you'd be counting my drafting lines.

well, you can either draw it not to scale and make it deceptive to try to prove an incorrect point, or you can draw it right and show the truth.

I added the lines for you that the axles actually rotate around. Since one is pointing up, and one is pointing down, they will not take the same path.

 

[frankies off road]

With this proto kit , we used 9.5" shocks I have wasted 1.75 of front shock travel and 2" or rear shock travel on compresion using 2" bump stops.

We are installing 12" travel shocks to see how that does and see if we can free up more travel.the rear is fine and will soak up the 12" travel for sure,the front may be limited even with 10" travel, but why not use longer shocks when we are wasting almost a full 2" of up travel.and in the real world it may just get that extra leverage to acually use more front travel.

these pics are with the sway bars hooked up..

 

[Walking Eagle]

With this proto kit , we used 9.5" shocks I have wasted 1.75 of front shock travel and 2" or rear shock travel on compresion using 2" bump stops.

We are installing 12" travel shocks to see how that does and see if we can free up more travel.the rear is fine and will soak up the 12" travel for sure,the front may be limited even with 10" travel, but why not use longer shocks when we are wasting almost a full 2" of up travel.

these pics are with the sway bars hooked up..

What are you going to use for 12" travel shocks, and what are you going to do for shock mounts?

 

[frankies off road]

What are you going to use for 12" travel shocks, and what are you going to do for shock mounts?

working with bilsteins and shock eye adaptors,

 

[Walking Eagle]

Pretty photos of carboard

hopefully this will show what's going on when you drop brackets at either end. The triangle can represent either raised axle brackets, if you cut out the middle, or a normal arm if you cut off the peak. I can't believe I've reduced myself to this.....

 

[Walking Eagle]

working with bilsteins and shock eye adaptors,

Cool, it'll be interesting to see what more you get out of it once the shocks aren't the constraint.

 

[Hayes]

I will cautiously make an observation here--even though I may be totally confused:

In the ongoing debate of "the axle will/will not follow the same arc with drop brackets, it seems that SUMO is assuming that the dropped bracket lifts the truck and keeps the radius arm at the same angle to the frame--making the arcs the same. This doesn't seem right to me. The springs support (and lift) the truck, not the radius arms--all they do is position the axle and define the arc.

Walking Eagle's high tech demonstration above, shows how dropping the (frame) bracket just changes the angle that the radius arm rests at relative to the frame. This does change the arc.

Now, if you add taller springs with the drop brackets....

Hayes

P.S. Excuse me if I've completely misread the conflict here.

Hayes

hopefully this will show what's going on when you drop brackets at either end. The triangle can represent either raised axle brackets, if you cut out the middle, or a normal arm if you cut off the peak. I can't believe I've reduced myself to this.....

 

[frankies off road]

Cool, it'll be interesting to see what more you get out of it once the shocks aren't the constraint.

I gota get it done soon i Have $7k worth of springs inbound

I think it will loosen up some more .shocks should be here in a few hours i hope.

post pics as soon as i get them on.

 

[LandCruiserPhil]

hopefully this will show what's going on when you drop brackets at either end. The triangle can represent either raised axle brackets, if you cut out the middle, or a normal arm if you cut off the peak. I can't believe I've reduced myself to this.....

Sign it and call it art and sell it on EBay

 

[SUMOTOY]

well, you can either draw it not to scale and make it deceptive to try to prove an incorrect point, or you can draw it right and show the truth.
.

Now your axles aren't horizontal (sorry that's a given), and you have a bump steer problem in both scenarios. You lowered the rear axle pivot, and raised the front axle pivot to correct for that. Remember, in stock trim, the axle rod doesn't mount in line with the axle. It mounts below the axle center. The arc of a two point mounting pivot will be the center of the axle. Put another way, if you only reverse the mounts exacly from the bottom and reattach to the top of the axle on the 80, you change the mounting height by exacly 4inches. That's not theory I actually measured my truck.

Let's look at an articulation scenario, it might help.
LG = LB = 42inches
3inch axle articulation

LG mount = axle piovt point lift 3in
LG Left side up 3inches, LG Right side down 3in. Left side moves forward from LB arc 1/16th inch, Right side axle arc moves back from LB arc the same amount = 1/16 th inch

LB mount = frame pivot point drop 3in
LB left side axle rod moves up 3inches, LB Right side axle rod moves down 3in. Left side axle rod moves back from LG line 1/16th inch, right side of axle rod moves forward from LG line the same 1/16th of an inch

Since the instant center of live axle is the other side of the axle, your axle arcs will be the same in either mounting under articulation.

I suppose you could argue a single scenario (and many have - it's hardly accepted - but I'll mention it) that if you go over a perfectly linear speed bump exactly perpendicular to it on a perfectly smooth road, you could have dual 3inch compression causing a 16th variance on axle arcs LG and LB. In ALL other dynamic scenarios, the axle arcs are identical during bump.

We need to get agreement on the arcs, before we can really address articulation. Then again, it's the articulation that really makes them identical.

Delete that drawing Heath, it's not right. Go take a look at your front axle mounts. We can indeed indeed raise them without changing the axle centerline.

Scott J

 

[SUMOTOY]

hopefully this will show what's going on when you drop brackets at either end. The triangle can represent either raised axle brackets, if you cut out the middle, or a normal arm if you cut off the peak. I can't believe I've reduced myself to this.....

It's a great exercise in reality. Try this now, do the OTHER side of the axle at the same time. If one axle rod is up the other is dropped = articulation.

You also need to show axles level in both scenarios at rest since that was a given in the equation. With level axles, the variance in individual arc is 1/16th of an inch at 3in. Combined, the variance is zero.

Same axle arc

SJ

 

[T Y L E R]

working with bilsteins and shock eye adaptors,

This will be my next mod .... Bilsteins tuned for the lift I'm running and the bumpstops I've got.


Looks nice Frankie!





TY

 

[Hayes]

It's a great exercise in reality. Try this now, do the OTHER side of the axle at the same time. If one axle rod is up the other is dropped = articulation.

You also need to show axles level in both scenarios at rest since that was a given in the equation. With level axles, the variance in individual arc is 1/16th of an inch at 3in. Combined, the variance is zero.

Same axle arc

SJ

Scott,
Am I missing the point? (post #107)

Hayes

 

[landtank]

WalkingEagle, just let it go.

 

[frankies off road]

This will be my next mod .... Bilsteins tuned for the lift I'm running and the bumpstops I've got.


Looks nice Frankie!





TY

thanks TYLER

you guys just remember who build what ya wonted when we get the kits in ,

frankie.....

 

[T Y L E R]

thanks TYLER

you guys just remember who build what ya wonted when we get the kits in ,

frankie.....

Kits? You selling the bilsteins and shock adapters?

I checked out the bilstein site, and it made my head spin, wasn't sure which model I needed to go with ..


TY

 

[frankies off road]

Kits? You selling the bilsteins and shock adapters?

I checked out the bilstein site, and it made my head spin, wasn't sure which model I needed to go with ..


TY

]stay tuned it coming soon

 

[SUMOTOY]

Articulation and axles

WE:
I'm only looking to figure out why we can't come to an agreement on the arcs here. Maybe it will help if we do the articulation exercise on the drawing. If you raise the right side by 3inches, you drop the left by 3inches, up to bind. That's the definition of articulation.

So, you need to look at articulation of 2 axles in both scenarios to see how the arcs are the same. We know at rod up 90 degrees to level, a 3in drop axle (LB) will be three inches shorter than the same rod mounted 3inches higher to the frame (LG).

However, the arc works the other way as well. As you drop the other axle from articulation, the frame drop mount pivot axle (LB) will be 3inches longer at 90 degrees down than the lifted axle (LG).

Why I claim they are the same arcs, articulation. The net difference is zero combining the two sides of the axle rods during articulation. I did a zoom to detail that on visio. In a static scenario, the axle centerline doesn't change. In a articulation scenario, the axle centerlines will net to zero difference in arc.

For your cardboard exercise and articulation, you will need to go 3D to see it. Make a right and left side, raise one wheel on the black line (call it right side), and lower one on the black line (call it left side). Then, use the green line, raise the left side and lower the right side. Your arc differences cancel out = defines articulation to interference/bind

This is a known property of a rigid axle suspension. You can in theory raise one axle rod, but in application, you also lower the other side.

Here's the equalities on the drawing board for you.

HTH

Scott Justusson

 

[SUMOTOY]

Scott,
Am I missing the point? (post #107)

Hayes

Not sure. I don't think so, but a single axle rod to the axle, isn't on our 80's. I'm a practical applications guy. I can look at a single axle rod and think we only have half the equation when we start to actually drive what we designed. The combined arcs of the axle rods exactly zero out any measured differences. If one rod follows the "shorter" path arc in lift, the other rod will follow the "longer" path arc in drop, by definition. And vice versa. Since the rod length is identical, and the rods were both statically horizontal, the differences in the arcs is exactly the opposite up vs down.

Therefore under articulation the arcs of the two axle rods on the same axle, zero out in drop frame pivot vs axle lift pivot mounting up to interference/bind.

I haven't done a drawing using a angled rod, since that wasn't a given.

Heath did a great job of cutting this all out. But that's only 1 dimension of two opposing and equal rod arcs. A guy like me looks at a live axle and says: "sure, now what's the other axle rod doing?" On a live axle, the exact opposite in fact.

SJ

 

[sleeoffroad]

What are you going to use for 12" travel shocks, and what are you going to do for shock mounts?

Well, hell. I wrote this in another thread. Might as well mix this one up completely and post the link here. No way we can confuse this thread more that what it is.

https://forum.ih8mud.com/showpost.php?p=1035651&postcount=27