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3/4 rear is coming :)

Posted: Sun Mar 20, 2005 10:35 am
by christover1
After a bit of video, photo, and thinking study, I have realised my shocks and/or shock bushes are way past their best..It's picking the front up and bouncing more than normal (been like it for a while)..
Although it was mostly driver error that caused my latest flop, ie bad line and a oops on the throttle, I believe the poor shocks is contributing to Frog's poor stability lately. The shocks and bushes are around 8 years old. At speed on the highway, especially when loaded with gear, full tank etc, it gets the sways and shimmies happening, more so after bumps, corners or side wind....
If I need to get new shocks, it must be time to fit a 3/4 eliptic on the rear, as I have all the other bits, now, bar the u-bolts, and the tank is out the way, already...
Any excuse for another mod :)
Still a just thought, but would like any input on whether the shocks could be a roll over/flop prob..and do I need a track bar? I will only be doing a small 3/4, ie not very long on the upper 1/2 leaf.
Probably re-use the locating hole in the leaf as a length guide?
Shock length/type can be worked out after fitted, can re-use my shox temporarily. Have done some searching, mostly this is all covered, but any more advice/warnings/opinions are appreciated.. thanx.
christover

Posted: Sun Mar 20, 2005 1:47 pm
by nicbeer
If you do it. make sure ya take a lot of pics.

Trac bar shouldn't be needed if its only a small one. Does Grimbo run one?

cheers

Posted: Sun Mar 20, 2005 7:53 pm
by christover1
nicbeer wrote:If you do it. make sure ya take a lot of pics.


Ok Will do :)

nicbeer wrote:Trac bar shouldn't be needed if its only a small one. Does Grimbo run one? cheers


Nope, I guess thats a good point, can always decide that later.
cheers .....christover

Posted: Sun Mar 20, 2005 8:06 pm
by Bad JuJu
nicbeer wrote:Does Grimbo run one?



Have I missed something..... I thought Grimbos was not going anywhere... Someone told me it was just a cubboard on wheels :finger:

Posted: Sun Mar 20, 2005 9:40 pm
by nicbeer
should have said did he run one.

Posted: Sun Mar 20, 2005 11:18 pm
by MY45
christover1 wrote:
nicbeer wrote:If you do it. make sure ya take a lot of pics.


Ok Will do :)

nicbeer wrote:Trac bar shouldn't be needed if its only a small one. Does Grimbo run one? cheers


Nope, I guess thats a good point, can always decide that later.
cheers .....christover


Unless the 1/4 spring is really small yes yu will want one coz up hills/ledges it will get a bounce up, and is your 1/4 spring isnt going to be that long why are you doing this mod as you will gain SFA. Have the 1/4 leaf fairly long and run a track bar, that way you will have mad flex and a control'd axle :D :armsup:

Posted: Sun Mar 20, 2005 11:27 pm
by nicbeer
Anyone know if you can fit a 3/4 rear if into NT if the tank is the std item. Is this needed to be moved to do a 3/4

Posted: Mon Mar 21, 2005 12:03 am
by oozuk
you will nee to run longer shocks and move the upper shock mounts more inbord to accomidate for the longer stroke length needed for the 3\4 eliptic

Posted: Mon Mar 21, 2005 8:00 am
by grimbo
Chris with SPUA you won't need a track bar. I have never had axle wrap problems int he 7 or so years I have run my setup. You will need to extend shock mount stec to gain the benefit of the 3/4 setup. On hill s and ledges the 3/4 doesn't get afected at all as the force of the axle moving up keep sit all locked together. Very steep downhills with articulation can open it up a bit more than you ar used too but I have no dramas

Posted: Mon Mar 21, 2005 9:06 am
by christover1
thanx all, much appreciated.
I like to keep my mods small and simple, more affordable, more reliable and easier to do.
Main thing that stopped me doing this till now, was throwing away good shox and the fuel tank issues....now these reasons are gone.
Nic the tank filler gets in the way of the upper leaf on that side...and 3/4 is easier on a narrow track as the top leaf sits flat on the chassis, so fabbing is easier.
track bar is probably more necessary with higher power/lower geared or super softly sprung situations, I guess.
Will determine upper leaf length, today, keeping the length as such so it don't get bolted to the chassis part thats curved.. I think that be better for keeping it aligned.
I do have space for longer shox, with the bodylift and no tank under there, but exhaust may need re aiming.
Until I drive it, its all only theories, but I believe it will behave reasonably the same closed up, as it does now.
I already got the bouncing happening, which I think is the shox/bushes, but offset rims exaggerates all the issues, too.
thanx again all
christover

Posted: Mon Mar 21, 2005 1:19 pm
by moose
nicbeer wrote:Anyone know if you can fit a 3/4 rear if into NT if the tank is the std item. Is this needed to be moved to do a 3/4


look where your fuel filler neck is !!!!
goes between chassis & spring pack !!!
(NT & WT !!)
you will have to change the filler position into the tank !!
& a 2" bodylift helps !!! (you run the new filler neck above the chassis , between the body , into the top of the tank !!)

Posted: Mon Mar 21, 2005 1:38 pm
by nicbeer
Cheers Moose.

BL on way.

cheers

Posted: Mon Mar 21, 2005 2:06 pm
by christover1
ok I got started. only with the tape measure and pencil :)
but I only have front springs to cut up ???
good side is, length is right if keeping spring locator position. ie it keeps shackle angle rightish and the u-bolts will clear crossmembers, and spring mount plate will be in good spot for a bumpstop thing, etc.
talked my self out of a short upper leaf, positioning of crossmember would mean toooo short to go to the bother.
down side of using my 1/2 a front spring is, its got a bit less arch and is a little thicker, so limitting a fex a tad.
tho this could be a good thing, meaning more moderate fex, and less strain on unis, shafts etc, and more stability, because of sideways strength. who knows ???
guess all the thinking/theory won't be as good as suck it and see.
I can always change the upper leaf later, if I not happy.
fitting werk will be the same, anyway. so long as I wait till I am happy with flex, before fitting new shocks.
christover

Posted: Mon Mar 21, 2005 2:13 pm
by nicbeer
How are you mounting the upper spring? U bolts i am guessing.

Do you need to cut off the original mounts for the shackles? Just thinking of trying it out and can always convert it back to original, also in case of getting a sticker from the cops.

cheers

Posted: Mon Mar 21, 2005 2:19 pm
by christover1
nicbeer wrote:How are you mounting the upper spring? U bolts i am guessing.

Do you need to cut off the original mounts for the shackles? Just thinking of trying it out and can always convert it back to original, also in case of getting a sticker from the cops.

cheers


yep, two u-bolts straight to chassis, (thats why NT's are easiest) and when happy with shackle angle etc, will drill thru a locating stud/nut/bolt or something.
Yes will need to cut off the shackle mount, and the bumpstop plate, and any tank brackets that get in the way..less things need cutting off if you do a shorter top spring. One possibility id a u-bolt each side of the chassis crossmember

I hoping to use axle mounting plates to fit the spring to the chassis, like Joey did on the Bruiser (engineer was happy with that)

christover

Posted: Mon Mar 21, 2005 9:29 pm
by Luigi Malone
Is the 3/4 lip legal ? Or must you get it certified ?
Luigi.

Posted: Mon Mar 21, 2005 9:36 pm
by christover1
Luigi Malone wrote:Is the 3/4 lip legal ? Or must you get it certified ?
Luigi.


any mod to chassis should and must be engineered.
engineers will certify 3/4 if its locked out for road use, and only unlockable with tools. my mates also needs a warning sign on the dash. christover

Posted: Mon Mar 21, 2005 10:32 pm
by alien
wouldnt it be awesome if "tools" meant a split pin the required pliers to get it out? at least it'd be just a case a case of 'yoink' and you're off... rather than pulling out the socket set etc... hey now theres an idea =P weld the socket head onto the nut so you dont need to hunt for the right size... just stick in the ratchet bit and youre set!