HELP - explaining correct positioning for Anti-tramp bar

[MNC]

Hi Guys,

Been spending some time under my cruiser and realised that the later model bodies (with petrol tank under floor instead of under drivers seat) have very limited space to weld in an Anti-tramp rod... bloody fuel tank gets in the way...

So I've read some threads and need some advice.

I'm thinking of using a tractor Top Link as my bar and setting up directly over the rear diff head (offset) and over the rear drive shaft (as this is the only direct access to a cross member) much like Wopass Mach 1 model:



The Tractor link has ball joints at each end which I reckon will not limit flex in anyway but my concerns are:

1. Do I have to go with a triangulated set up? &

2. Is it absolutely necessary to have the Anti tramp bar in the centre of the diff??? If so why?

I see that Wopass changed to this setup (which I cant do due to the fuel tank being in the way) which Richard has commented on (and I need to check that my below assumption is correct)

http://i248.photobucket.com/albums/gg193/wopassx/DSC05297Large.jpg

...The big difference is that a cruiser has an off set diff so what Wopass has done is good because the anti tramp is in the middle of the diff.

The diff on a hilux is in the middle so therefore the rotation point can only be on top of the diff to make it work right so that both springs move up and down wihout stress...

I think the ball joints at each end of a tractor link should sort this out right?



I really can't place it in the centre of the diff - there is just no room there.

Advice appreciated (sorry no photo of gas tank in the way )

[Fakey]

Will it fit off to the side of the pumpkin like my one, it works fine an doesnt affect axle articulation at all.

[niblik]

1. Do I have to go with a triangulated set up?

nope.. but the triangulated arm is used in conjunction with the shackle to keep the twist (front / back rotation) from the diff from occuring but allow the movement, ever so slightly, back and forth with diff/spring movements..

2. Is it absolutely necessary to have the Anti tramp bar in the centre of the diff??? If so why?

i personally dont think its necessary as if you have enough strength in the arm and attached points on the diff/chassis, it should stop any rotating of the diff. in an ideal world it would be a good move yes, but if, in your case, ya have the oober tank in the way, then to one side is suffice..

and yeah, i think the eyes at both ends of that arm would create a lot of free movement that wouldnt bind up and create a hinderance upon axle movement/articulation.

[MNC]

Will it fit off to the side of the pumpkin like my one, it works fine an doesnt affect axle articulation at all.

Na, your truck has the older style body with the petrol tank under the drivers seat - thats why you have all that room under the body for the bar in the centre.

Would have been easier to explain if I had taken some photo's- sorry about that...

[Fakey]

Haha yeah pics would make it easier. im not too familiar with the fancy under floor tanks Is there any room one the short side of the diff?

[MNC]

1. Do I have to go with a triangulated set up?

nope.. but the triangulated arm is used in conjunction with the shackle to keep the twist (front / back rotation) from the diff from occuring but allow the movement, ever so slightly, back and forth with diff/spring movements..

So I reckon by mounting that Top Link on the top of the diff head that the two springs mounted to the rear of each side of the diff and other end fixed to the chassis - should form the two bases of the triangle (if you get my drift).

2. Is it absolutely necessary to have the Anti tramp bar in the centre of the diff??? If so why?

i personally dont think its necessary as if you have enough strength in the arm and attached points on the diff/chassis, it should stop any rotating of the diff. in an ideal world it would be a good move yes, but if, in your case, ya have the oober tank in the way, then to one side is suffice..

and yeah, i think the eyes at both ends of that arm would create a lot of free movement that wouldnt bind up and create a hinderance upon axle movement/articulation.

Cheers dude, that is exactly what I wanted to hear.

[sig]

from memory ideal setup is the same lenght as driveshaft and in the same plane but obviously above it .scroll back thru fj40petes build thread .he had a wicked lookin tramp bar on his 40

[MNC]

Haha yeah pics would make it easier. im not too familiar with the fancy under floor tanks Is there any room one the short side of the diff?

No worries

Yeah there is room on short side but the top of the diff head is closer to the center and reinforces the exact part that I am trying to stop from twisting (back and forwards that is).

Cheers

[Fakey]

It shouldnt matter which side or how far away from the diff head it is as long as the diff mount is close to the same height as the top of the diff head itll give the same effect (Ie have enough leverage to stop the housing twisting),
thats my theory from all the pics ive seen anyway, sure someone will correct me with their oppinion

[Fakey]

from memory ideal setup is the same lenght as driveshaft and in the same plane but obviously above it .scroll back thru fj40petes build thread .he had a wicked lookin tramp bar on his 40

An then he broke it , too much power

[MNC]

from memory ideal setup is the same lenght as driveshaft and in the same plane but obviously above it .scroll back thru fj40petes build thread .he had a wicked lookin tramp bar on his 40

Yeah, I found a few pics of Pete's set up but again he doesn't have the fuel tank in the way (he has a custom fuel tank that sits behind the rear diff):

His track bar is alot like wopass's Mark 2 version:

[MNC]

Cheers for all the comments guys.

Think I'm going to go with Wopass Mark 1 version using the tractor Top Link.



Lets see how it goes

[wopass]

nah dude go with MK2, i screwed the pinion off and S bended the leaves even with MK1 in there


this one was the buisness

http://s248.photobucket.com/albums/gg19 ... 6Large.jpg

[rokhound]

Just remember that you are trying to counteract a rotational force. And the reason some are saying on top of the diff head is because it is the highest point on the axle housing, which gives the track bar a better leverage factor against said rotational force.
Does that make sense?

Obviously the more power you put into the axle, the higher the forces will be and the more strength you need to build in to counteract this, hence the Y shaped bars on the gruntier V8 rigs.

[niblik]

and the 3b 40's....

aye rok?

huh rok?

huh?

aint that right...?

torque monster..

[darinz]

I have no experience with leaf springs at so this is coming from a different point of view.

I would think the it would be very important that the track bar arm length is the same as the distance from the centre of the axle (where the spring is fixed) and the pivot point on the chassis.
The reason for this is to do with pinion angle change. Obviously being exact doesn't matter a lot but if it was to far out then during travel the track bar would cause the diff to twist and stress the springs etc.
The way to think if this is that the springs are effectively the lower trailing arms and the track bar is the upper trailing arms. Whne the arms are all the same length then the pinion angle doesn't change. When the uppers are shorter then under extension the pinion points further up the further the suspension is extended.
So the springs are fixed to the axle so control axle movement. If you were to then fit a track bar that is too long or short then it would work against the springs.

But like I said I have never played with leaf springs so this is a theoritical observation and maybe very insignificant.

[niblik]

pretty much correct darinz yeah..

thats why the driveshaft has a slip yoke in it though as when the leaf compresses, it flattens out thus lengthening, ever so slightly..

vice versa the other way..

[lilpigzuk]

correct positioning for anti-tramp bar

next to here

[wopass]

ahhh ahahahahha hah ah hahahha

[niblik]

correct positioning for anti-tramp bar

next to here

no no fella.. thats where they reside... it'd be somewhere near this.....



snickers

[Bulletproof]

The nearer to the centre of the diff the better otherwise the spring nearest to the anti tramp rod will be stressed with leaf springs.
I have also set the front point ofr the anti tramp rod in line with the front spring hanger so they are parallel at a higher level.

The middle of the diff on mine hardly goes up and down at all because of the spring in the middle on the top of the diff so the anti tramp rod means the angle of the diff is constant at all times and the drive shaft doesn't go in and out.

Cheers Richard

[petefj40]

The nearer to the centre of the diff the better otherwise the spring nearest to the anti tramp rod will be stressed with leaf springs.
I have also set the front point ofr the anti tramp rod in line with the front spring hanger so they are parallel at a higher level.

The middle of the diff on mine hardly goes up and down at all because of the spring in the middle on the top of the diff so the anti tramp rod means the angle of the diff is constant at all times and the drive shaft doesn't go in and out.

Cheers Richard

I like your setup Richard.
Got any pix of it for these guys?

[MNC]

The nearer to the centre of the diff the better otherwise the spring nearest to the anti tramp rod will be stressed with leaf springs.
I have also set the front point ofr the anti tramp rod in line with the front spring hanger so they are parallel at a higher level.

The middle of the diff on mine hardly goes up and down at all because of the spring in the middle on the top of the diff so the anti tramp rod means the angle of the diff is constant at all times and the drive shaft doesn't go in and out.

Cheers Richard

OK, so having a fixed rod (ie no slip joint like the drive shaft) offset above the diff head in a 40 would actually create more stress on the springs and pinion (than having none at all)??? Think that is what is being said here...

Alright, back to the drawing board.

Might see if there is room for some sort of A arm setup to get round the petrol tank (from centre of the diff to both chassis rails).

Or might just leave without the rod and change to 80 series rear after breaking my first pinion

[Smurf]

Bulletproofs set up, from page three of his thread

[wopass]

and still i see nothing there to stop the axle wraping up smashing off the pinion and bending leaves...

you need to triangulate to stop axle wrap, the top bar just helps a little but not enough when you really give it a hard time and thats when you want your shit to NOT break

hilux=light and pussy 4cyl diesel
landcruiser=heavier,more power and bigger foot

make it stronger bro

[Sadam_Husain]

Like wop says triangulate it and make it strong coz the rotational forces are huge, my springs dont wrap coz they are the origional heavy duty LWB truck ones but I ended up with my spring perches distorting because of the rotational forces and ended up pinging my pinion off?

[petefj40]

and still i see nothing there to stop the axle wraping up smashing off the pinion and bending leaves...

you need to triangulate to stop axle wrap, the top bar just helps a little but not enough when you really give it a hard time and thats when you want your shit to NOT break

hilux=light and pussy 4cyl diesel
landcruiser=heavier,more power and bigger foot

make it stronger bro

Good point wopass.
But I still thought it looked pretty trick. I know Richards is only a diesel but it is supercharged and he gets it going in some pretty demanding places.

[Bulletproof]

Like wop says triangulate it and make it strong coz the rotational forces are huge, my springs dont wrap coz they are the origional heavy duty LWB truck ones but I ended up with my spring perches distorting because of the rotational forces and ended up pinging my pinion off?

Hi Marty
Dont you have a solid 12mm piece of vertical steel welded on to strengthen the spring Perches ?

My perches did that also so I beefed them up.

Cheers Richard

[Sadam_Husain]

Hi Marty
Dont you have a solid 12mm piece of vertical steel welded on to strengthen the spring Perches ?

My perches did that also so I beefed them up.

Cheers Richard

Yeah Howie made some new spring perches for it out of some box sextion with the ends capped off to strengthen them up... not sure what will bend or break next? I've got a pic somewhere but it takes hours to find it on photobucket on my dialup connection

[niblik]

triangulated arm with a shackle broski..

doesnt need to be a massive triangle, but trianglular non the less..