Suspension travel upgrades on an 80

[SUMOTOY]

Here's what I believe Nay to conceptualize

WE:
I think what you aren't keeping in mind is that both rods are flat, as in horizontal to the frame. What that means in terms of how you got there is irrelevent to arc. Nay is speaking to 'effective' lift" as being the same in terms of frame drop mount" or lift axle mount

Here's how I interpreted his meaning.
LG = LB
<G = <B = horizontal
Pivot Centerline of G = Pivot Centerline of B
Axle Centerline of G = Axle Centerline of B

Then, as you can see:
Arc of G = Arc of B

Your geometry assumes to much. Remember, we are only speaking to "Effective" lift in either scenario causing the axle to be horizontal. You are assigning that an equal value to both scenarios. That's not assumed, nor calculated. Nor does it matter really, because Nay is speaking to effective lift vs clearance.

As such, you would have the following as your arcs (See picture in post 98).

Cheers

SJ

 

[landtank]

SUMOTOY that diagram doesn't even make sense. What the hell is an axle rod? If you are referringf to the leading arms then the axle's arc would be centered at the frame bracket and not half way down the arm.

 

[Walking Eagle]

SUMOTOY that diagram doesn't even make sense. What the hell is an axle rod? If you are referringf to the leading arms then the axle's arc would be centered at the frame bracket and not half way down the arm.

Ya', those diagrams are amussing. In order for the axle to follow that path the radius arm would have to get shorter as it goes up and down!

Oh, and if they have the same amount of lift, the axle is going to be the same distance vertically below the frame. You've drawn flipped arms with 3" less lift than the dropped bracket - as evident by the frame being twice as far from the road in the second figure.

I feel much better now Sumotoy - thanks...

 

[landtank]

Ya', those diagrams are amussing. In order for the axle to follow that path the radius arm would have to get shorter as it goes up and down!

not at all....just bend in the middle

 

[SUMOTOY]

SUMOTOY that diagram doesn't even make sense. What the hell is an axle rod? If you are referringf to the leading arms then the axle's arc would be centered at the frame bracket and not half way down the arm.

Rick:
As I indicated, I can't get mud to take the circle from the axle pivot point. So I halved the value on both. Double the value in both scenarios, you have the same arc in both scenarios.

I'll work on gettin mud to take it. I spent a while to get the above loaded.

SJ

 

[SUMOTOY]

Ya', those diagrams are amussing. In order for the axle to follow that path the radius arm would have to get shorter as it goes up and down!

Oh, and if they have the same amount of lift, the axle is going to be the same distance vertically below the frame. You've drawn flipped arms with 3" less lift than the dropped bracket - as evident by the frame being twice as far from the road in the second figure.

I feel much better now Sumotoy - thanks...

I think you confuse post #2. Effective lift of the arms is what Nay is speaking to. As such, call it increased clearance if you want. This drawing only reflects what's given. 2 axle rod mountings horizontal, each increasing effective lift (clearance) by the same amount.

If you want to speak to 3inches of lift, or 5 or 6inches of lift, as in spring lift, more calculations and givens are necessary before any assumptions can be made about arcs. I don't see that listed in any post prior to 15 or 18. In the case of adding just spring lift, why drop the rear pivot point at all?

Maybe Nay can clarify his thoughts in post 2

SJ
visioly impaired for now

 

[Walking Eagle]

I think you confuse post #2. Effective lift of the arms is what Nay is speaking to. As such, call it increased clearance if you want. This drawing only reflects what's given. 2 axle rod mountings horizontal, each increasing effective lift (clearance) by the same amount.

If you want to speak to 3inches of lift, or 5 or 6inches of lift, as in spring lift, more calculations and givens are necessary before any assumptions can be made about arcs. I don't see that listed in any post prior to 15 or 18. In the case of adding just spring lift, why drop the rear pivot point at all?

Maybe Nay can clarify his thoughts in post 2

SJ

Hummm..... Nay wasn't talking about a lift in post 2 huh?

At 4" of lift with raised axle mounts, you can go with a shorter arm and retain excellent angles. If this type of project is meant for real use, you need to think about every millimeter of clearance you can gain at every point. This is why drop bracket kits are absolute sh*t. Don't ever drop your frame mounts - raise your axle mounts instead to achieve the exact same effect but with dramatically improved clearance instead of dramatically worsened clearance.Nay

As far as why use drop brackets on the frame? That's been discussed to death on other threads. Short version is it restores more stockline axle movement than caster plates at the same time sacrificing some clearance.

Keep back peddeling, you'll get somewhere eventually.

 

[SUMOTOY]

Crorrected Arcs

Here's the correct arcs as reflected with two rods of the same length, both horizontal. FYI, nothing fancy in the arcs, I drew the top, then dragged the exact copy to the bottom one. SEE POST 98

SJ

 

[SUMOTOY]

Hummm..... Nay wasn't talking about a lift in post 2 huh?



As far as why use drop brackets on the frame? That's been discussed to death on other threads. Short version is it restores more stockline axle movement than caster plates at the same time sacrificing some clearance.

Keep back peddeling, you'll get somewhere eventually.

Ok Heath, let's try it: 4inches of lift caused Nay to lower the rear frame pivot mounts by 4inches to make the axle rods horizontal to "restore more stockline axle movement". He found himself like TRU, hanging up on rocks.

So he proposes another Option, put the rear pivot points back, then...

As Nay says in #2, same 4inches of lift caused Nay to raise the front axle mounting points 4inches to make the axle rods horizontal to "restore more stockline axle movement"

Given: Both scenarios rods are horizontal, Rods are the same length, axle centerline is the same, frame pivot centerline is the same, axle center to fender measure is the same, axle pivot centerline is the same, radius of arc is the same.

Same arc. See corrected pic on post 98

Are you sure you don't want to speak more specifically to reduced articluatoin and/or interference? That would be a more appropriate conclusion. The arcs are identical, the resulting movement on them could cause one option to have reduced articulation or increased interference isssues. That's not your claim in 15 or 18.

SJ

 

[frankies off road]

back on track here,4" up5.5 down, I hope this pic is working.
pics on next page

 

[ElJefe]

Humm...

...
As suspension lift is added if the new shock length is selected properly then there should be no problem. I think the other issues I mentioned before cause a bind or interference before the shocks become a stopper. All these issues are definetely case specific to each of our trucks. tires,lift etc play a huge role in this.

Kirk

This is completely dependent on longer bumpstops. If you retain the stock shock mounts, and the stock bumpstops, putting a longer than stock shock will bottom out the shock before the bumpstop makes contact... period. If you want to use a longer shock you have one of two options.

1... longer bumpstops. This in effect trades uptravel for downtravel. If you have large tires and your uptravel is otherwise limited by tires, longer bumpstops are a necessity to keep the tires out of the engine bay anyway, so this is a doable approach. If you just put longer shocks in without the bumpstops and bottom them out they WILL blow. Maybe not the first time but soon enough.

2... taller shock mounts. This lets you take a taller shock, and move it up so it will work with otherwise stock bumpstops. So your uptravel remains the same and your downtravel is incresed by the added length of the shocks. This is what I have done on other trucks and works very well. I run this setup with my 71 Bronco. I have 12" travel 7100 Bilsteins running 2" lift and stock bumpstops. Never bottomed one out. I actually have room for 14's but they would not add anything without other serious($$$$) suspension mods. This gives me about 4 inches of Uptravel to the stock stops and 8 inches of downtravel. Rarely is a wheel dangling.

For all of you looking for inexpensive long mounts for eye-eye shocks... the Bronco crowd uses the shock mounts off of F*rd F250SD trucks which are available individually from Ford as just a mount. They are cheap, stamped out of 1/4 inch plate, about 14 inches long and have an eye mount on top. PLENTY heavy for the cruiser. Best bang for the buck IMHO. No reason they couldn't be used on cruiser's as well...

Currently $32 per pair...

Just to give you an idea... the flat mounting area where the 2 holes are is around 5 inches tall.

 

[Walking Eagle]

For all of you looking for inexpensive long mounts for eye-eye shocks... the Bronco crowd uses the shock mounts off of F*rd F250SD trucks which are available individually from Ford as just a mount. They are cheap, stamped out of 1/4 inch plate, about 14 inches long and have an eye mount on top. PLENTY heavy for the cruiser. Best bang for the buck IMHO. No reason they couldn't be used on cruiser's as well...

Currently $32 per pair...

Just to give you an idea... the flat mounting area where the 2 holes are is around 5 inches tall.

40 series guys use them too - Mine has them, though some cut the bent part and straighten them out - they're a bit longer that way and for me they fit into the fender opening better (see photo in other post).

 

[Walking Eagle]

Given: Both scenarios rods are horizontal, Rods are the same length, axle centerline is the same, frame pivot centerline is the same, axle center to fender measure is the same, axle pivot centerline is the same, radius of arc is the same.

Same arc. See above corrected pic
SJ

Your corrected picture has one vehicle with a lift, and one without. not the right comparison.

And no, if you raise the axle brackets, moving the axle straight down from the end of the radius arm, it is not the same radius of arc, cause the distance from the axle to the pivot is now different. Remember A squared plus B squared equals C squared from school? You went to school right? Your new radius is C, not A like the other arms. You've just created a big L arm (as I drew). You've gained ground clearance for sure, but you haven't created the same effect as dropping the arms on the frame.

I'm sick of this dead horse.... I"m sure everyone else is sick of the dead horse. Admit your wrong, appologize, and lets get on to something more productive.

 

[Nay]

Ok Heath, let's try it: 4inches of lift caused Nay to lower the rear frame pivot mounts by 4inches to make the axle rods horizontal to "restore more stockline axle movement". He found himself like TRU, hanging up on rocks.

So he proposes another Option, put the rear pivot points back, then...

As Nay says in #2, same 4inches of lift caused Nay to raise the front axle mounting points 4inches to make the axle rods horizontal to "restore more stockline axle movement"

I'm reading this thread and it appears my rig is pretty damn extreme

None of these drawings is particularly relevant because they show way to much travel along an arc. You take a 30" radius and move 5" each way along that arc and you don't see real world differences. Draw to that scale and see what you get. You should also notice that I recommended shortening the arms to a mid-arm for better clearance. The entire middle of this thread is accounted for with adjustable arms.

The problem with this thread is not geometry. The problem is that "increased travel" is a subset of a much larger issue, and just addressing travel may mean you are spending money to trade problems. I pick on drop brackets as the most classic example: you get a better ride and better arcs in exchange for another problem you'll need to solve (clearance). Next step will be more lift, and then you're back to the arm angle problem again.

The domino effect is the very nature of attempting to go hardcore and stay entirely bolt-on. Long radius arms are another classic - better ride and less climbing resistance as a trade for reduced clearance (at least this comes free on an 80) and a tendency to "unload" the front end on steep climbs. My initial post was designed to reflect the need to think outside of bolt-on solutions if you want to actually gain anything material beyond RTI as you increase suspension travel.

The question shouldn't be "how do I increase travel?". If you are asking this question on the basis of need, then the complete question should be "how do I design a hardcore FZJ80 to hit the hardest trails without compromising road manners?" You'll get straight to the right answer by asking the second question...and to a (pit) stop along the way by asking the first.

Take a look at Frankie's pics. I don't think the 80 uses more than 6"-7" of front end travel, so you have a lot of shock to "waste". The key is not to waste the travel upwards and have smallish tires. Better to waste it on unused down travel and have larger tires. Balance is a lot more important than travel on smaller lifts.

Nay

 

[SUMOTOY]

I'm reading this thread and it appears my rig is pretty damn extreme

None of these drawings is particularly relevant because they show way to much travel along an arc. You take a 30" radius and move 5" each way along that arc and you don't see real world differences. Draw to that scale and see what you get. You should also notice that I recommended shortening the arms to a mid-arm for better clearance. The entire middle of this thread is accounted for with adjustable arms.

The problem with this thread is not geometry. The problem is that "increased travel" is a subset of a much larger issue, and just addressing travel may mean you are spending money to trade problems. I pick on drop brackets as the most classic example: you get a better ride and better arcs in exchange for another problem you'll need to solve (clearance). Next step will be more lift, and then you're back to the arm angle problem again.

The domino effect is the very nature of attempting to go hardcore and stay entirely bolt-on. Long radius arms are another classic - better ride and less climbing resistance as a trade for reduced clearance (at least this comes free on an 80) and a tendency to "unload" the front end on steep climbs. My initial post was designed to reflect the need to think outside of bolt-on solutions if you want to actually gain anything material beyond RTI as you increase suspension travel.

The question shouldn't be "how do I increase travel?". If you are asking this question on the basis of need, then the complete question should be "how do I design a hardcore FZJ80 to hit the hardest trails without compromising road manners?" You'll get straight to the right answer by asking the second question...and to a (pit) stop along the way by asking the first.

Take a look at Frankie's pics. I don't think the 80 uses more than 6"-7" of front end travel, so you have a lot of shock to "waste". The key is not to waste the travel upwards and have smallish tires. Better to waste it on unused down travel and have larger tires. Balance is a lot more important than travel on smaller lifts.

Nay

I agree so far Nay. The geometry of the arc is the same, so it's not a geometry problem (and I wasted a lot of time getting visio to talk to mud, ). The issue is articulation restriction, and interference restriction caused by the raising of the front pivot point.

It still would appear that 'some' lift would be required to actually flip the rods upside down and remount on top of the axle. But if that gives 4inches of additional clearance WITH 4 inch lift,, life is good. Better I'd argue than (actually you did Nay) 4 inch lift leaving the fronts attached where they are, or even dropping the rears pivot point, cuz you haven't added any clearance with that lift.

I can't speak to drop articulation, since the rear setup would need to be looked at next. yikes!

SJ

 

[SUMOTOY]

Your corrected picture has one vehicle with a lift, and one without. not the right comparison.

No, actually both reflect installing 3inch spring lift.

A) Assume 0 lift is horizontal axles, 15inches from top of rim to bottom of fender.
In my drawings then:

B) Top picture is 3inches of lift (add 3inch springs), measured from the top of the rim to the bottom of the fender = 18inches, axle rod is horizontal, raised front axle mounting point on centerline 3in

C) Bottom picture is 3 inches of lift (add 3in springs), measured from the top of the rim to the bottom of the fender = 18inches, axle rod is horizontal, dropped rear mounting point on centeline 3in

Arc of A=B=C with a 48 inch axle rod horizontal. At 0 degrees the centerline of the front axle is 48inches from the pivot centerline in A,B and C. At 90 degrees, the centerline of the front axle is 0inches from the pivot centerline in A,B and C.

ARC A=B=C.

The frame location in relation to the axle rod will cause interference and articulation problems, as is also indicated by the drawings. You are confusing axle>frame interference with arc. This isn't a geometry problem of different arcs.

SJ

 

[Walking Eagle]

No, actually both reflect installing 3inch spring lift.

And around and around we go - do you not see the extra lift you've put into this?

 

[SUMOTOY]

Man, TO SCALE?!

Ok WE
I didn't realize that you'd be counting my drafting lines. Here's a revised drawing reflecting the equal frame height. I even added the 'other' scenario in each drawing, so you don't make me draw all this to scale. It really doesn't change anything, this isn't a geometry problem. Lift of the frame is caused by the 3inch springs. The frame is closer to the arms in LG, because the arms are closer to the frame. That is an articulation/interference problem. The arcs are the same, the lift is the same.

If you want the visio drawing, let me know, you can do it to scale if you want. It won't change anything i'm afraid. There is no "additional lift" with a set of 3inch axle springs, it's equal in both. And actually it shows the additional *clearance* by raising the front pivot with a 3in spring lift, same axle arc. Nay had it right back in post #2


Scott J.
Thank god for visio zoom

 

[1000-oaks]

Tyler, whats with the avatar? It has been bothering me for a while.

Pardon me if it's already been said (skimmed the thread), looks like Henry Rollins to me. Black Flag frontman and has done some films, was the "troubleshooter" for the suit in "Heat".

 

[T Y L E R]

Pardon me if it's already been said (skimmed the thread), looks like Henry Rollins to me. Black Flag frontman and has done some films, was the "troubleshooter" for the suit in "Heat".

I hate to insert chat into this technical 'discussion' .. ;p


KOaks, the avatar peeps are talking about was not Rollins .. It was my 'other' avatar I borrowed from my gay personals ..

This one:





TY