Achieving extreme rear flex?

[t0x1k]

i am die hard ford as anybody, but shit i have never heard of anybody who wouldnt run a set of leaf springs because of it???

go 63's with a shackle flip and youll have all youll ever need.

I don't see any shocks, is that true? Does it ride bad on the road? I was thinking of just ditching shocks(switch them to the front for more travel) for the time being after I decide on a mod to do.

 

[4x4junkie]

the only way a wheel will get traction is if it can reach the ground.if you have a regular leaf spring setup(or any suspension for that matter)that doesn't allow the axle to droop till the wheel contacts earth it doesn't matter how much pressure that spring could potentially apply,a wheel on the ground with ONLY IT'S OWN WEIGHT will give more traction than a wheel hanging in the air.

having said that,if an axle is able to swing so both wheels can reach the ground and to weight of the vehicle is supported by only one of the springs on that axle,that weight is still distributed across both wheels,though the ratio of that weight distribution will be detemined by the ratio of axle lengths on either side of the working spring.

if,on the other hand the axle is retained on the droop side so that it can't swing right to the ground then only the tire on the compression side is getting traction.this also means that all the drive load is being taken up by one axleshaft.

long and short of it...a wheel in the air will not drive your truck.
at all.

I think he meant that a "dislocating" suspension setup (revolver shackles, uncaptured coils, etc.) will not convey near as much traction as a properly engineered setup that will also still allow the tire to reach the ground, the spring on which can still maintain some contact pressure of the tire against the ground.

A truck with short, stiff uncaptured springs is not gonna work well, period.


As for cops hassling you (OP), were you making a bunch of noise after 10:00 PM?

 

[t0x1k]

I think he meant that a "dislocating" suspension setup (revolver shackles, uncaptured coils, etc.) will not convey near as much traction as a properly engineered setup that will also still allow the tire to reach the ground, the spring on which can still maintain some contact pressure of the tire against the ground.

A truck with short, stiff uncaptured springs is not gonna work well, period.


As for cops hassling you (OP), were you making a bunch of noise after 10:00 PM?

No, town is mostly a bunch of old people. Putting in my lift I got them called twice. Now every time I make even my impact wrench go off they roll by. I live in a small town which hates anything noisy. Its a shame, cause 2 people on every block own a car with some kind of loud exhaust, and I get hassled.

How do a belltech supporting a belltech sound? Im not going for street hugging performance, but don't want my ass end going sideways.

 

[86 slo-vo]

I don't see any shocks, is that true? Does it ride bad on the road? I was thinking of just ditching shocks(switch them to the front for more travel) for the time being after I decide on a mod to do.

i ran no shocks for a while on the street, it sucked but i got used to it so it didnt bug me. but once i put some on there wasnt going any going back. the shocks were way short so i pulled them for the trail but it gave me some spring wrap.

No, town is mostly a bunch of old people. Putting in my lift I got them called twice. Now every time I make even my impact wrench go off they roll by. I live in a small town which hates anything noisy. Its a shame, cause 2 people on every block own a car with some kind of loud exhaust, and I get hassled.

How do a belltech supporting a belltech sound? Im not going for street hugging performance, but don't want my ass end going sideways.

2 belltech's togather sounds like a whole lot, arent they over 7 inches?

if it were me id stick with a single shackle.

 

[gwaii]

I think he meant that a "dislocating" suspension setup (revolver shackles, uncaptured coils, etc.) will not convey near as much traction as a properly engineered setup that will also still allow the tire to reach the ground, the spring on which can still maintain some contact pressure of the tire against the ground.?

the problem with a leaf spring is that it can only put pressure on the axle to the point it reaches it's free amount of arch(the amount it would have laying on the floor,not attached to anything).once you go past this amount of arch in droop,the spring is no longer pushing down on the axle...the axle is actually pulling down the spring.so what's happenning is the spring is holding the axle up.
in slo-vo's pics above on the rock you can see that the left rear tire is about to leave the ground...it no longer has any weight on it.if the truck is driven up an obstacle any further,this wheel will be off the ground.at this point it is hanging from the leaf spring.if the u-bolts were removed from this side at this point,disconnecting the diff from the spring,the wheel would drop to the ground.not only drop,but would have a measureable amount of pressure on it from the other spring pressing down on the whole solid diff.
(you can see how this works by placing a board so it's ends are on two scales,then stand off towards one end of the board.there will be weight on both scales,but there will be more on the one you are closer to.the same thing happens with a live axle suspension that is supported only by the spring on one side...both wheels will have pressure on them,but there will be more on the side closest to the supporting spring.now,while standing on the board,get a friend to lift the far end of the board.no weight will be shown on the scale on that side,just as there is no weight on a tire when it's end of the axle is held aloft by an overextended leaf spring.)
since the spring is being used to locate the axle as well as support it,this would not be an ideal way to get underway of course...but if the axle were to be located by another means such as a 3 or 4 link and the springs simply used to support the vehicle then the wheel could be allowed to drop,still have pressure on it,and drive the vehicle.

a semi-eliptical leaf spring with the axle bolted to it for location can never achieve extreme droop and still be a driveable vehicle because the two functions of locating and supporting are inherantly working against each other.improve one,the other will suffer.
for droop,the optimum leaf spring will be a very soft one with huge arch and a very long shackle to take up the huge length changes caused by this large arch needing to flatten out and arch.
for location the optimum spring will be as flat as possible(even with a slight negative arch so the axle center is in line with the spring eyes)and very stiff,with a very short shackle.
to balance these two factors you must compromise somewhere.

A truck with short, stiff uncaptured springs is not gonna work well, period.

exactly...uncaptured indicates the location function has been comprimised.this was the problem i had when i tried the drop links.

 

[gwaii]

in this picture you can see that while fairly well extended,the left rear tire still has weight on it
9look close,the bottom of the sidewalls are bulged).

this pic gives a good overall view.
the fully extended right front tire is still supporting the truck.at the rear you can see what i was talking about with the tire on the side of the supporting spring carrying more weight(note sidewall bulge)though the extended side is still carrying weight.

if the extended side of the axle were attached to the springs,this sort of flex would not be achieveable.plus,by using links to locate the axle,a short,stiff spring could be used giving the truck stability in normal use.all shocks stay in place and there are no sway bars or other things to unhook.

 

[The Jester Race]

That is ****ing nuts. So how unstable is that thing in off camber situations?

Check this out. You have to wade through the typical pirate bullshit, but lots of good info here.

http://www.pirate4x4.com/forum/showthread.php?t=846526



-Jester

 

[gwaii]

That is ****ing nuts. So how unstable is that thing in off camber situations?


-Jester

that's the key...it's very stable.i went through all the usual avenues trying to get decent flex but stabillity was always the problem.this setup gave me the flex i wanted and the stabillity i needed.
once i hit that balance in flex and function,i was able to stop constant rebuilding and concentrate on useing it.

 

[hockeyryan]

in this picture you can see that while fairly well extended,the left rear tire still has weight on it
9look close,the bottom of the sidewalls are bulged).

this pic gives a good overall view.
the fully extended right front tire is still supporting the truck.at the rear you can see what i was talking about with the tire on the side of the supporting spring carrying more weight(note sidewall bulge)though the extended side is still carrying weight.

if the extended side of the axle were attached to the springs,this sort of flex would not be achieveable.plus,by using links to locate the axle,a short,stiff spring could be used giving the truck stability in normal use.all shocks stay in place and there are no sway bars or other things to unhook.

love those pics

 

[4x4junkie]

the problem with a leaf spring is that it can only put pressure on the axle to the point it reaches it's free amount of arch(the amount it would have laying on the floor,not attached to anything).once you go past this amount of arch in droop,the spring is no longer pushing down on the axle...the axle is actually pulling down the spring.so what's happenning is the spring is holding the axle up.
in slo-vo's pics above on the rock you can see that the left rear tire is about to leave the ground...it no longer has any weight on it.if the truck is driven up an obstacle any further,this wheel will be off the ground.at this point it is hanging from the leaf spring.if the u-bolts were removed from this side at this point,disconnecting the diff from the spring,the wheel would drop to the ground.not only drop,but would have a measureable amount of pressure on it from the other spring pressing down on the whole solid diff.
(you can see how this works by placing a board so it's ends are on two scales,then stand off towards one end of the board.there will be weight on both scales,but there will be more on the one you are closer to.the same thing happens with a live axle suspension that is supported only by the spring on one side...both wheels will have pressure on them,but there will be more on the side closest to the supporting spring.now,while standing on the board,get a friend to lift the far end of the board.no weight will be shown on the scale on that side,just as there is no weight on a tire when it's end of the axle is held aloft by an overextended leaf spring.)
since the spring is being used to locate the axle as well as support it,this would not be an ideal way to get underway of course...but if the axle were to be located by another means such as a 3 or 4 link and the springs simply used to support the vehicle then the wheel could be allowed to drop,still have pressure on it,and drive the vehicle.

a semi-eliptical leaf spring with the axle bolted to it for location can never achieve extreme droop and still be a driveable vehicle because the two functions of locating and supporting are inherantly working against each other.improve one,the other will suffer.
for droop,the optimum leaf spring will be a very soft one with huge arch and a very long shackle to take up the huge length changes caused by this large arch needing to flatten out and arch.
for location the optimum spring will be as flat as possible(even with a slight negative arch so the axle center is in line with the spring eyes)and very stiff,with a very short shackle.
to balance these two factors you must compromise somewhere.




exactly...uncaptured indicates the location function has been comprimised.this was the problem i had when i tried the drop links.

Again, I say if the spring DOES have enough movement to not reach it's free arch so soon, you'd have some spring pressure pushing down at the wheel (not just leverage transferred across the axle).

The Chevy leafs previously mentioned will have much more travel than the shorter RBV springs the OP is running. It would be much better to swap to the Chevy leafs than to have a "disconnecting" or otherwise unsecured link in the suspension (Slo-Vo's wheel is drooped down much further than if he still had his RBV springs).

Very impressive ramp pics, though it's a bit hard to see exactly what's going on with the suspension... (pics are kindof fuzzy & dark, though I don't seem to see a spring at all under the right-front) Have you done much hill or rock climbing with that setup?

 

[Will]

There's a coil-over straight down from where the winch motor and the spool meet.

To me, this gets filed in the If you say so drawer. It's out of my ken.

 

[Sasquatch_Ryda]

Yea there are coil springs in-boarded as there is no engine in the front of that baby!

 

[4x4junkie]

Ah ok, I see it now, though just barely (had to lighten the pic up).

Inboarding the springs is certainly much better than having something that disconnects itself during flex. However I'm now wondering how that fits into this discussion of things that "disconnect" for extra droop after the spring "runs out", as this is something completely different

 

[gwaii]

Ah ok, I see it now, though just barely (had to lighten the pic up).

Inboarding the springs is certainly much better than having something that disconnects itself during flex. However I'm now wondering how that fits into this discussion of things that "disconnect" for extra droop after the spring "runs out", as this is something completely different

note the thread title...it's 'achieving extreme rear flex'.
that's what i was discussing,along with the fact you can't get extreme rear flex with a semi-eliptical spring setup that uses the spring to locate the diff without losing control over the location of the diff,and therefore run into driveability and stabillity issues.

you can get somewhat improved flex,but that is not in the thread title,and this forum subsection is not 'somewhat improved suspensions',it's 'extreme suspensions'.

as for the discussion of what happens when the diff drops from the spring,this was simply to explain how allowing this to happen is not only a good way to achieve extreme flex,but will also help in stabillity and overall traction by keeping all the wheels on the ground.there seems to be some confusion as to how this works,generally by people that have never tried it or seen it in action.just because you don't understand something does not mean it doesn't work.

long and short of it...if you want to acieve extreme rear flex,and still be able to control your truck,a link type suspension is needed.
what you use for springs is less important.

 

[4x4junkie]

Ok, I follow you on that... But we were specifically discussing devices that disconnect the spring from the frame to give additional droop and you come in here and post something with inboarded springs that has nothing of the sort (at least you've not mentioned anything about it having that and nothing can be seen in those pics). Sasquatch was simply stating that a rig with, say, 20" of rear flex that comes from springs that work for that full 20" is going to be a whole lot better than a rig that the spring works for only 12" of travel, the other 8 coming from a "disconnecting" shackle, and I fully agree with him.

You also have to remember the OP appears to be still running the stock-type suspension up front. To have such extreme articulation in the rear and (guessing) only a max of maybe 35° total up front (no mention of what mods he's done up there... it's likely as little as 10°!), to have such an imbalance of front & rear flex is another recipe for disaster (I know this well from my Ranger that had supple rear springs and rock-hard front ones). Drop the stiff front tire down a ledge, up comes the rear & over she wants to go.
Maybe the OP needs to clarify what exactly his goals are here.

as for the discussion of what happens when the diff drops from the spring,this was simply to explain how allowing this to happen is not only a good way to achieve extreme flex,but will also help in stabillity and overall traction by keeping all the wheels on the ground.there seems to be some confusion as to how this works,generally by people that have never tried it or seen it in action.just because you don't understand something does not mean it doesn't work.

I don't know if this is directed specifically at me, but I DO know how it works. I HAVE seen where someone's floppy shackles unloaded on a hillclimb and made the whole rear of their rig start jacking itself up & down uncontrollably. I've also seen setups with fully 90° of axle articulation relative to each other (quite common in the RC crawler world) and while this works great in rocks if you have a super-low CoG (and of course on ramps too), it doesn't work as well elsewhere (or if your CoG is higher, as is typical with a full-bodied vehicle).