JIM5.0

Virtually everyone uses Panhard bars on their Stang's. But in reading the Steeda Street Fighter kit, they use Watt's Linkages instead of Panhard bars.

I did a search on Watt's linkages, and the information pulled up was absolutely useless. Someone only saying "You can always go Watt's instead of Panhard" but there is little reason why.

Can someone break it down for me in detail?
1) What exactly are the advantages and disadvantages of each? (Please be as detailed as possible.)
2) When and why is Panhard better over Watts?
3) When and why is Watt's better than Panhard?

Sam Strano

1. PHB's are have inherent geometry changes because one end is at a fixed location aboe the ground, but the other moves up and down as the body does... and that makes the body move left and right as it happens. Watts links do not do that. Further a PHB will pull the body down when turning one way, and push it up and away in the other, Watts links don't do that. PHB's are cheaper and easier to install. Watts links cost more but work better. In fact you see a lot of solid axle cars having them, even some econoboxes... and other Fords.

2. Never better in function, a bit lighter. For drag racing a PHB is fine to do the job.

3. Anytime you want a more stable, predictable rear suspension.

For what it's worth, a Watts link is not a new invention. It's called a Watts link because James Watt, you know the steam engine guy, came up with it in the 1700's... not for a Mustang though it would seem that Fox suspensions might date back that far.

Talk to anyone who's run both, and if you find 1 out of 50 that says there is no difference I'd be shocked. I've had two, and will be adding one to my 2011 in the spring. I sell Fays2 and Steeda both.... I've had two Fays2, I might run the Steeda this time, but probably not as the car is an autocross car I would prefer the rod-ends of the Fays2 vs. the urethane bushings of the Steeda unit.

Sleeper_08

Further to Sam's comments here is an explanation of the WAtt's linkage

http://en.wikipedia.org/wiki/Watt%27s_linkage

Click on the diagram to see it move.

I'm one of the ones that have has both and would never go back to a a panhard bar and mine had poly bushings. The FAYS2 Watt's link provides a much more "stable" feeling when driving the car especially noticeable n right left left transitions such as in a chicane.

FastDEW

A few comments and questions:

I have seen two Watts configurations for the Mustang.

One type connects to the back of the differential using a single bolt on a modified diff cover. This seems to be not a good solution to me because it can sheer the bolt and in fact, I have heard of the bolt sheering on some (Saleen I think).

The other type I have seen uses a clamp on each side of the axle tube. This also seems to have problems as the axle tube was not designed to have clamp loads on it. These are thin walled axles and I could see the clamp causing deformation.

So - What is the best way to go if you were going to install a Watts link? My guess would be to use the clamp type and then spot weld perhaps so that it does not shift but you are not clamping so hard ont he axle tube.....

I would like to know what others think? What works well in practice and what others have seen as far as reliability and/or vehicle damage/axle damage????

Do the Watts link setups make a significant difference to a street only car? Perhaps someone who drives aggressively, but only drive street. No track. Is the Watts price worth it for somebody like that???

Noise? What are the differences in noise between the Watts and PHB?

trz06

If you talk to the folks over at MM, they will tell you that the rear suspension on the Mustangs has such little travel, that a watts link doesn't do much over a PHB.

They say, that the watts links benefits cars with more rear travel, like Crown Vics, and the like.

I have talked to the three "major" suspension companies on the Mustangs ( Griggs, Sam, MM) and I get 2 1/2 different answers on the benefits of a watts link for a street car and if they make a noticeable difference.

Norm Peterson

The only place I can think of where a PHB might hold the advantage over a WL is in circle track racing, where you might be able to use the PHB's asymmetric behavior to improve turning left (at some cost in right turning capability - which since you really don't ever want to be turning hard right at speed in this activity doesn't matter).


There is some possibility of reducing the "asymmetric-ness" of a PHB by chassis-mounting to the driver side (opposite to what's OE), at least for when you're adding throttle on corner exit. The intent is to use PHB asymmetry in such a way as to offset the driveshaft torque reaction and more closely equalize wheel loads in L vs R turn exits. NASCAR teams may be using this PHB arrangement on the two road courses.

You're probably give something up by doing that, but I don't offhand know what it is.


Norm

JIM5.0

Thanks so much for the info, this is exactly what I was looking for.

To help me better understand the motions the parts are put through, I dug up these visuals:

Watt's linkage geometries in motion (No car's suspension goes through this much motion, at least unless you are Duke's of Hazarding it):
http://www.youtube.com/watch?v=blDJ-bu3NLo&NR=1

Grapf of the motion of the rear diff's center point on a Panhard vs Watt's linkage
http://www.youtube.com/watch?v=a8cJCqWkfgk

Actual Watt's linkages on a 'Stang, I presume an SN95
http://www.youtube.com/watch?v=43_mH...eature=related

pascal

Are you gonna race this thing?
If not, the Panhard bar is plenty sufficient IMO and even so, Ford factory built race cars like the FR500C were put together with the OEM (non adjustable) panhard and no rear sway bar.
Of course, those cars had reinforced body shells with tubular control arms and very efficient coil over shocks, but still, this is something to think about...
I'd save my money and be content with the panhard bar.

Sam Strano

Not sure where exactly to start with my answers.

How about the notion that if you aren't racing the car is doesn't matter? I don't agree... and again will point out that if you talk to most anyone who's (and this is critical) run both you'll find a landslide in favor of a Watts link over a PHB. Already you've had two folks in this thread tell you that between myself and Sleeper08.

How about the notion that there isn't enough travel to matter. Yeah, ok. <rolleyes>. When I did a Watts on my other live axle car (2001 Z28 with about the same amount of travel and car weight) there was enough change that I was able to take a lot of wheel spacer out I had to previous run with a PHB (and the PHB had to be set so the body was shifted to compensate for the arc). I was able to take 8mm out of each rear wheel, that's almost 3/8" per side on a lowered car. And that car also has a very long factory PHB setup, in fact pretty much setup exactly the same way. It's simply not true that there isn't enough travel for it to matter.

Regarding factory race cars. I bet if you read the rules you'll find the Watts link isn't legal as it's not on the production car.

Let me finish with this. Between Griggs, MM, and myself there are three differences in thinking. We all think we are right. When in doubt you have to weigh the information you are given and decide for yourself. I frankly think they are both nuts for running TA's which add a lot of unsprung weight--but they think that's right. I prefer the 3 link setup, it's what you see on solid axle race cars when the rules don't dictate something else. GT1 TransAm type cars.... those are 3 links, not TA's. And in fact if I could somehow swap to a 3 link on my Camaro, I would in a second. But yet, one of them likes a Watts setup, the other does not. But I prefer a frame mount type over the setup that Griggs uses.

Do yourself a big favor and forget the names associated with things, including my own. You should not just assume anyone is right just because you've heard of them. I've seen a lot screwy things, IMHO, from "names you know" over the years. Look at the details, listen to the reasoning, decide for yourself. Also when it comes to listening to advice on the 'net, it's always tough. I believe it's best to more heavily consider the findings of people who've directly compared various items over those opinions that are based on theory only. Most folks haven't had the opportunity to try a lot of things, and I don't know of anyone who can try EVERYTHING, it's just not possible. But I've run a lot of various setups, shocks, springs, swaybars, Watts links vs. PHB's, etc. I do think practical knowledge is important.

And finally... I also thought that a Watts link wasn't that big a deal---once upon a time. Then I tried one, then two, and anytime I have the option to run a Watts link, I will.

Sam Strano

Well, there is no issue with the axles deforming.... The axles are strong enough to lift the car from, or rest on jackstands. Beyond that, the clamps on the Fays2 are pretty large meaning the load per square inch is not very high.

As for the styles. I don't like the diff cover mounted units. You can modify a diff cover, but it's not exactly meant to be dealing with cornering loads. And the frame mount types require no modification to anything, not even a new diff cover. And in the case of the Fays2, the propeller has two (not just one) big, high quality roller bearings inside that allow the propeller to rotate freely making life a lot easier on the bolt.... and use high quality bolts. I imagine that the Saleen unit was having some sort of bind and that's what was causing the bolt failures.

Yes, they matter on the street. You can just trust the rear end better. I would never recommend a Watts before a good set of shocks because they are cheaper, and frankly the best first step to dealing with a lively rear end over bumps. But the Watts link does add a sense of trust and stability that the shocks just can't. Again, see Sleeper's comments.