Outer Limits 4x4 Board

Suspension Gurus .. what is the pro's and cons of these setups in the rear of a serious 4x4 ...
From what I can tell the biggest disadvantage of the watts link is the fact it hangs down a bit low ..

Is that all .. I would think that the watts link may imporve the roll centre of the vehicle

We have been designing and playing with watts links for ages and work well.
Only prob is as you said to work properly with good flex the mount has to hang down too low.

How exactly does a Watts link work. From what I saw on tv, there are 2 bars/rods connected to the diff, up into the centre of the car, mounted onto a bracket.

What is allowing it to move up and down? As its practically solid, the bars will stretch and be useless.

Or have I got it all wrong.

take a look under a falcon

where they connect to the diff there is a swivel section like a shackle with the center attached to the diff and it can move

kinda hard to explain needs a pic

but watts links are way better then panhard, i wouldnt bother about a panhard rod

The landrover series 2 (edit* series 2 disco) came with a watts linkage in the rear.

http://en.wikipedia.org/wiki/Watts_linkage

Disco2 Watts linkage

and race cars generally have the pivot mounted to the chassis and the arms to the axle. Much easier to adjust the roll centre height, if you need to.

and back to the original Q, with a Panhard Rod, as the axle moves from bump to droop the bar describes an arc which moves the axle sideways, wheras a Watts linkage allows the axle to have a totally vertical path as the suspension cycles.

In a Watts link, the theoretical roll centre is the centre of the pivot, and a Panhard is where the rod intersects the axle/vehicle centreline.

can a panhard set up limit flex off road or is it more of an on road handling issue???

I think its more of a geometry issue than anything.

rick130 wrote:and race cars generally have the pivot mounted to the chassis and the arms to the axle. Much easier to adjust the roll centre height, if you need to.

I was just thinking if there would be any benefits of mounting the linkage like this. If nothing else it would eliminate the problem of the linkage haning down too low. Am I right in saying that to allow the diff to drop further you would need a longer linkage to allow the rods to move outward more?

can't see your pic toughnut!

i was wondering same. if you could mount the link on a slightly higher stanchion on the diff, and therefore have a longer linkage

I don't like the idea of the Watts linkage in the rear of rear axle because of the ground clearance issues.
In my opinion, the best way to install a Watts linkage for offroad use, is to install it horizontally on the top of the axle, instead of installing it on the bottom like the following pics. But i think the concept is the same.
What's the opinon of everyone else?

Might be difficult to mount the Watts linkage setup on top of the diff and still have clearance for top links?

I can't picture what happens to the linkages at full droop? I suspect it could get nasty.

Scott

anyone know if a watts setup would work on a leaf sprung vehicle (rear), that has lost of wheel travel and also pivot in spring eyes.

-Scott- wrote:I can't picture what happens to the linkages at full droop? I suspect it could get nasty.

Scott

Are you taling about the pic's above ..
I would say that they are for a very limited travel setup.. The longer the wheel travel the longer the cross bar would need to be. The panhard would only become the limiting factor in total droop (like if you jumped it) but in an articualtion situation I would not see it being a huge issue (All this is my theory .. I have no practial knowlegdge of any of this)

Thats a really nice street setup. Could be worth having a bit more of a look. I'm looking at running an "A" frame rear but I've heard of a few getting loaded up and breaking. This could be a way of either assisting an "A" frame or not worrying about an "A" frame at all. HMMMMM. Too many choices.

Fellas, thats a race car that the CAD drawing is for and is in a completely different location, not a 4WD design of the watts linkage at all. If you look at the pics further up, like the Disco2 one, the watts linkage is setup over the top of the diff and the rocker sits up and down rather than flat. The 4WD setup give better travel as the link bushes work in the proper rotational direction.

As others have said, the length of the pivoting link is one of the factors that determines how much vertical travel you can have.

A watts linkage will lead to bump/roll steer if used on the front axle.

beebee wrote:Might be difficult to mount the Watts linkage setup on top of the diff and still have clearance for top links?

I don't think so. The Watt's link design is very compact, when compared to an A-frame design!
On my BJ40, in order to install an A-frame, i had to remove the fuel tank from it's original place. With a Watt's link i think it should fit easily.
I am yet to see a good Watt's link on a 4x4 or a system like the one i described (installing it horizontaly on the top of the diff housing).

BJ40 3B wrote:

beebee wrote:Might be difficult to mount the Watts linkage setup on top of the diff and still have clearance for top links?

I don't think so. The Watt's link design is very compact, when compared to an A-frame design!
On my BJ40, in order to install an A-frame, i had to remove the fuel tank from it's original place. With a Watt's link i think it should fit easily.
I am yet to see a good Watt's link on a 4x4 or a system like the one i described (installing it horizontaly on the top of the diff housing).

what sorta joints are you goin to be able to use to get decent vertical movement, and not bind up?

antt wrote:

BJ40 3B wrote:

beebee wrote:Might be difficult to mount the Watts linkage setup on top of the diff and still have clearance for top links?

I don't think so. The Watt's link design is very compact, when compared to an A-frame design!
On my BJ40, in order to install an A-frame, i had to remove the fuel tank from it's original place. With a Watt's link i think it should fit easily.
I am yet to see a good Watt's link on a 4x4 or a system like the one i described (installing it horizontaly on the top of the diff housing).

what sorta joints are you goin to be able to use to get decent vertical movement, and not bind up?

That's the bit I can't get my head around. They need to flex in two directions. Vertical link looks a lot simpler - and with an offset pumpkin, you can get the link alongside the diff, rather than needing to be on top or behind.

Scott