Panhard Bar vs Watt's linkage

[Nelson]

I just looked up Panhard Bar in Wikipedia and it says that a better choice for small cars would be something called Watt's Linkage. Does anybody know anything about this?

 

[PSJ]

Hi Nelson!
Some people here can answer better than I, but here's my understanding:

A Panhard bar limits lateral (side-to-side) axle movement, but makes your rear axle travel in an arc (again, side-to-side) as the suspension compresses/decompresses. For us non-RWA box Spridget owners, it can help you run wider tires without rubbing on the inside of the fenders, in addition to providing more stable/predictable handling. THe length of the bar dictates the radius of the arc, with the widest (longest) bar possible being preferable.

A Watts Linkage also limits lateral movement, but makes the axle travel straight up and down - no arc expressed or implied!

The Watts Linkage is technically superior, but less commercially available. I have a "Frontline Spridget" Panhard on my '71 Midget, and I'm happy with it. If there was a Watts Linkage equally well engineered, and cost-comparable, I would rather have a Watts Linkage.

Safety Fast!

Phil

 

[Gundy]

Frontline makes a rear linkage called a RTL that sure looks nice
but I went with the tried and true panhard.
Frontline's panhard is very similar to Speedwell's unit.
Here is a link to the install stuff for Frontline's RTL.
https://www.moss-europe.co.uk/graphics/uk/instructions/FLD30931_SEMI_Inst.pdf

This is a link to a discussion of the options for Spridget rears.
https://books.google.com/books?id=V3STrys...ard&f=false

 

[Hap Waldrop]

I used both on Spridget race cars, and my choice would almost always be a panhard bar, due the lesser amount of sub structure required to mount it, as for the rear end moving about where a third link running between the rear end and the chassis would come in.

Ok with being said, most street car need none of this, they are just subjected to the force a race would be to justify needing this, often time folks look at panhard bars set up when running their tire widths at the max, so they can keep them off the fender when conrnering.

I suggested a panhard bar to David Harrison (Gundy) on his Bugeye, he's running larger than normal tires and wheels for that car and getting a bit of tire rub when hard cornering. Winners Circle, www.spridget.com , makes nice bolt in panhard bar set up for Spridgets.

In perfect world for performance set up on the rear of Spridget, where I don't abandon what is already there for a coil over set up, I would do a set with rear trailing arms and mount the springs in the bracket (1/2 eliptic car) where they are not pinched by tightening the U bolts, meaning the trailing arms set the rear end, not the leaf spring allowing the spring to be just a spring, and not trailing arm, this would eliminate all spring wrap during hard braking and acceleration, and then add a third link to set pinion angle. Ok with tha being said the tire you can put on your street car, would never allow you achieve the sort of G forces needed to justify this on street car, so a apnhard bar for you guy pushing wide tires, maybe a rear sway bar for you guys pushing it to keep the outside rear wheel/tire form squatting under hard conrnering, other than that, thats about as trick as stret car rear suspension needs to be, anyhting else would be over kill and bling, and nothing needs to be done unless you are really asking alot of the car in the corners, racing or autocrossing or running wide wheels and tires.

 

[Trevor Jessie]

I may fit a panhard bar to prevent future rubbing. My tires were rubbing on hard cornering, but after fitting all new bushings the tires did not rub. I'm guessing that before long the rubbing issue will return as the bushings start to break down.

 

[Gundy]

I have relatively new bushings/springs etc and had not experienced
significant rub till I let ol Hap flog her a bit.
Hap demonstrated Mimi's limits and man, you could smell rubber
the whole way around the track. It was intoxicating.
I probably could get by without the panhard but ya never know when Hap
might want to take it for a leisurely drive or I lose my good sense
and seriously haul some butt on Devil's Fork Road.

I going to start with the panhard and see how it drives before any further modifications.
I really like Speedwell's tubular 7/8 front sway bar.
It's purdy too.
"But, Honey....it matches the panhard and looks so nice!"
Funny how a wife gets skittish when I talk about go fast items but
if I frame it in cosmetic terms terms she's game.
Women...don't ya just love 'em.

 

[aeronca65t]

That Frontline setup is also called a "Mumford link". It was/is popular on Mallock race cars. Good for keeping roll-center correct as well as limiting sideways motion of axle.

~Click here~ to see more about these.

Another way of limiting side-to-side motion on live axle cars is through the use of an "A frame" (there are several names for this device). The A frame seems to be more popular on European racers.

You can see an example of an A frame on ~this A-35~. You'll have to click on several of the lower images on the page to get a better view of the actual A frame.

(Spridgets are based on the A-35, so there's a lot of shared parts)

 

[Hap Waldrop]

The A frame often referred to as the wishbone as well, we put those on vintage Midget race car, It performed well, but limited where the exhaust could be, and the ideal place to mount at the rear end housing was the drain plug, it take a fair bit of fabrication, another iss with this is the supsension travel and where excatyl you have the fornt mounts located on a wishbone, it doesn not have to be in the exact palne of the trailing arms or rear fornt spring mounts as long as supsension travel is very little like a rae , but as supsenion travel increase, you better be aware of ths like on street car, you could get into trouble with this set up real quick, we saw this take out a car at the 24 hours of Daytona it sheared 5/8" heim joint in half, not once but twice. Overall if you're going to do this on street car, the panhard bard is the most user friendly set up , and the one I still prefer on my race cars.

 

[aeronca65t]

Yeah, I recall that the drain plug in the diff was the best place to attach the back of the wishbone.

And of course, it's better if that end of the wishbone is in double shear.
(the two front rod-ends too)
You're right......not a simple deal.

I built the panhard rod on my race-Spridget from scratch after looking at pictures on the Frontline website.
Mine's worked well for 7 or 8 years now.

 

[hpmowog]

Technically, a Watts link is a better set-up, but unless your car has a lot of body roll, there's unlikely to be a noticeable difference in performance. On my SCCA car, I've got a Watts link, and on my vintage car I've got a panhard rod. Both of them do the job.

 

[Gary_D]

I need to stabilize the rear end of my 67 Sprite, as I only have 1/4" to 1/2" of tire cleaaence between the inside of the fenders. Have been looking at the Speedwell unit, but I am affraid that my exhaust and muffler will interfere with the bar that goes to the rear. My exhaust is run up over the rear axle and the muffler is tucked up next to the fuel tank on the drivers side. I was thinking about fabing my own(a mirrored image) and having it on the passengers side of the car. Anyone see any problems with my idea? Also, where could I find the necessary fittings? Any input will be aappreciated.

 

[aeronca65t]

If by "fittings", you mean "rod ends", ~try here~

 

[Gary_D]

Thanks Nial, using the correct terminolgy helps. The rod ends were what I was referring to. What are you feelings about fabing the pan hard for the passenger side. Is there a reason for installing on the drivers side?

 

[aeronca65t]

Honestly, for a street car, I don't think it would matter that much. I've seen them fixed to the right and lest side of the chassis.

You're just trying to keep the axle "centered" and the forces that shift it off-center come from both sides.

By the way, here's a wishbone kit I just noticed:

https://www.go-fast-parts.com/5708981.html

My fabbed panhard rod:

 

[Gary_D]

Thanks for the help and photos Nial. Think I am going to give it a go on fabbing my own.

 

[twas_brillig]

Some info from the Winners Circle from a few days ago:
Panhard rod: THE PRICE IS $225.95. EVERYTHING IS INCLUDED THAT YOU WILL NEED TO INSTALL.
THE DOUBLE BEARING HUB KIT IS $379.95. THE KIT INCLUDES: 2 HUBS, 2 INNER BEARINGS, 2 SNAP RINGS FOR THE INNER BEARINGS AND 2 SEALS. YOU USE YOUR STOCK OUTER BEARINGS. WE DO HAVE IN STOCK, STOCK OUTER BEARINGS [$16.95@] AND SEALED OUTER BEARINGS [$33.95@].
Not a commercial, but figured I'd pass on the info that these folks were good enough to provide as it's something I'm thinking about for our BE.

Doug

 

[Gary_D]

I want to thank all of you that responed about a panhard rod. After looking at alot of photos and reading all I could, I spent about $100 for DOM tubing, some 1/4" X 2" cold rolled flat bar, acouple of rod ends and a handfull of grade 8 bolts. Started on the project last week in the evenings working in the driveway and took Little Red into my shop today were we have a Mig welder. Worked at it for about 5 hours and enjoyed every minute.End result--NO TIRE RUB. It also really seems to glue the rear down. I'm a happy camper.

 

[Gundy]

I like the way the panhard tidies up the rear myself.
This is my Speedwell Engineering panhard rod installed.