The Packard torsion ride system

[SMOKEY44211]

Having recently purchased a 56 Packard with torsion bar supension I have a question for those who may know the answer. (I'm very impressed with the knowledge with most of the contributors to this and other forums within this group). For those who may not be familier with it, there is a single torsion bar for each side of the car that is connected to the front and rear wheels. When the vehicle is raised you can push up on the front wheel and the rear wheel goes down and vice versa. There is a second tosion bar at the rear wheels on each side to maintain ride height and control the see saw effect. A compensator motor controls the amount of twisting force that is in this second bar. By virtue of this ride height is maintained independant of the amount of weight carried when the vehicle is returned to level ride attitude via this compensator motor. According to the Packard manual the theory being that only have of the energy jounce of a bump to the front wheels goes into tha car and the rest is transmitted to the rear wheels with this system. I must say that even with very old bias ply tires this is the finest riding car I have ever driven. So the $64,000 question is howcome no other manufacturer(to my knowledge) has incorperated this system in thier product line? Are there any faults. Potential race car application advantage/ disadvantage? -------------Phil

 

[GregLocock]

The original Mini used linked fore aft suspensions, I think, at least in prototype form. The Lotus active ride cars also used cross linking between corners.

The obvious disadvantage is traction, on a rear wheel drive car. As the front wheel rides over a bump the trailing rear wheel will also unload. You could get round that by upping the rear sta bar... but that would degrade the ride.

Also the setup as described would tend to oversteer a lot, you'd need a front sta bar. Ideally you'd also have an anti-warp bar, then you'd have complete control over the springing.

The crash guys would probably hate it, but appropriate use of breakaway features could minimise the downside there.

Fundamentally are you not trading off good pitch control against roll? Modern cars tend to annoy people far more with roll (head toss) than they do with pitch.

Cheers

Greg Locock

 

[Peter7307]

Smokey,
As Greg mentioned the original Mini and larger 1100 / 1800 (4 door saloons)used the interlinked suspension system developed by Moulton in the UK and used by British Layland in the Morris and Austin cars under the name "Hydolastic".
There was a later refinement using gas spheres called "Hydragas" but neither system provided for any form of self leveling.

The Citroen company in France used an interconnected system on the 2CV models and derivatives with one coil spring and push/pull rods connected to the wheels on the same side.
The arms connecting the wheels to the chassis were cast steel and acted as the dampers for the car.
The market was the immediate post was ravaged agriculturally based France and the engine was 375 cc air cooled flat twin and a four speed manual gearbox with a centrifugal clutch
The ride is very smooth but no provision for self leveling was provided since Citroen had a fully self leveling hydraulic system in their larger cars from the mid 1950's.

Pete.