Welcome! Glad you are here.

Thanks for replying and thanks for watching. I am not familiar with the Australian Falcons but lowering the watts link would have had the effect of lowering the roll center by the same amount. I've read this helped stabalize the car but the change was made as part of a much larger package of changes so it's hard to pinpoint what actually made the cars better. Here's a forum a friend of mine sent me that talks about the changes: www.fordforums.com/threads/whats-the-difference-between-ea-and-ef-l-rear-suspension.11130/ I hope this helps.

@@suspensionsexplained thanks for the reply and the link. I might have a play around with it and see what happens as it could be a nice cheap mod to tidy up the handling a little. I do know I have a couple of different holes to mount the upper arms to the diff housing but not as many as the later ones which had a few suspension variants. But yes, I appreciate your answer and the information that you freely put out in your videos. Looking forward to the next one!

That depends on your vehicle. What are you driving? Is this a Jeep?

@@suspensionsexplained it's the new suzuki jimny

it has solid axle on both front and rear

Shawn, i have a BSME from Duke University and an MSME from Georgia Tech. I also have 31 years experience in the auto motive industry focused on chassis design and engineering

Hey man, did you happened to work for Tesla back in the early model S days?

@@suspensionsexplained I love that KZfaq has provided a platform for the public to glean a ton of knowledge from a seasoned industry professional, what a time to be alive. I have a BSME from UConn and now work in the MEP controls industry, but the automotive industry fascinates me. Kudos to you for putting this knowledge out there, and I hope your channel takes off.

The roll center for a panhard rod is where the rod crosses the center of the vehicle. For a Watts link it is at the pivot point of the link where it attaches to the differentcial.

@@suspensionsexplained what if it’s not level?

Doesn't matter. it still forces the roll center to be where the link crosses the vehicle centerline.

@@suspensionsexplained thus Panhard link allow lower RC than Watts link, this may be relevant to choose among

That depends on other things. The axle is still moving with the suspension so there is still a lot of unsrpung mass. If the corners are rough, it will still cause the axle to bounce a bit and "skate" in the corner. Having said that, using a Watts link or Panhard rod will make the rear feel much more "planted" and confident in a corner. The vehicle will turn in more sharply and precisely and will feel much more confident.

I'm not sure if I'm saying this right, but I'll have a crack at it... If the control arms are triangulated from the top view, then the lateral motion is technically already constrained, so adding a Panhard rod would introduce bind (the severity would depend on the angles of the links and length of the rod), and would require deflection of some component for the suspension to travel. But if the links are parallel (top down view) the axle is free to move side to side so it can follow the ark of the Panhard rod without bind. So, to answer your second question... Yes, the design of the bushings would have to allow enough deflection for the design of the suspension or something will likely break, but not all 4 links will have that problem. All of that bushing deflection is less than ideal for performance, so this particular suspension is probably making a sacrifice in that aspect to gain somewhere else like packaging or something. A 3 link with a watts link or Panhard can operate bind free, so solid spherical rod ends work fine. Technically, all non-parallel 4 links will bind in roll... they try to twist the axle, but the amount is usually minimal. I have, however, seen ladder bars break front rod ends and I suspect it's due to that kind of bind.

Just to clarify, most of what you are saying is correct, however, a non-parallel 4 link will not bind in roll. With 4 links, there are 2 degrees of freedom available: roll and vertical movement. There is no binding. Introducing a Panhard rod or even a Watts link will introduce binding though. The use of bushings in the links will eliminate the binding and allow the system work. The Watts link adds control and lateral stiffness while the bushings add comfort. The best of both worlds.

@suspensionsexplained sorry, i meant non-parallel in side view. The side view swing arm will cause the axle to rotate forward on the side that compresses and back on the side that extends. Unless the links are parallel and SVSA is infinitely long.

You are correct that a Panhard rod has fewer parts but it is also asymmetrical. The placement of the roll center could indeed be lower with a panhard rod but only if the rod is installed in a low position which may not be desirable for ground clearance and structural reasons since the roll center will be at the height where the rod crosses the centerline of the vehicle. It is also true that a Watts link will have one of the links below the roll center while the Panhard rod is right at the roll center but there are ways to mitigate this somewhat, which is what the Raptor does. For shear performance, I stand by my claim that a Wats link is superior, even if it is more complex.

What you are saying is true if the links are all perfectly stiff and the joints are all heim joints. But if the joints are rubber bushings then a Watts link will still be an improvement since the compliance of the rubber allows the Watts link to do its job. It will also be a much more comfortable car to drive in.

@@suspensionsexplained ...what you're describing is a total compromise. What John is saying holds true. Very, very, very few people will install sloppy rubber bushings in a triangulated 4 link so they can add a Watts...

Actually, you will need some compliance in the other links if you want to use a Watts link or a Panhard rod. Both try to move the roll center away from where the 4 main links place it so you MUST have some compliance in the bushings in order to stop the whole thing from binding. What both do is allow you to have high lateral stiffness (for good cornering and steering response) while using relatively soft bushings to get longitudinal compliance for good ride and comfort. As far as compromise is concerned, absolutely EVERYTHING in suspension design is a compromise of some sort. You just have to have your priorities set before you start your design.@@anonymousplanetfambly4598