Interconnected suspensions

[747heavy]

Zero roll stiffness, hmmm.... This is only when one wheel is off the ground and ignoring the weight of the un sprung parts?

Why would that be the case?
Ignoring for a moment, that it would be practical difficult to run "Zero" roll stiffness, as you will either block out your damper, or more likely touch the ground with your floor, I can´t see why you would need one wheel off the ground?

Take a look at your proposed layout, with a heave spring inbetween two rockers and no
ARB or corner springs.
Use this setup at the front and the rear.

Both wheels on the ground and applying a sideforce at the CoG, what will happen?

[ringo]

Zero roll stiffness, hmmm.... This is only when one wheel is off the ground and ignoring the weight of the un sprung parts?

Why would that be the case?
Ignoring for a moment, that it would be practical difficult to run "Zero" roll stiffness, as you will either block out your damper, or more likely touch the ground with your floor, I can´t see why you would need one wheel off the ground?

Take a look at your proposed layout, with a heave spring inbetween two rockers and no
ARB or corner springs.
Use this setup at the front and the rear.

Both wheels on the ground and applying a sideforce at the CoG, what will happen?

I wouldn't want the wheel off the ground, I was stating a case where zero roll stiffness will happen. If it must happen with an ARB and without corner springs, one wheel must have zero force through it, and it's parts must be weightless. This only happens if that wheel is off the ground.

In the question you posed to me, take it easy, I'm going off of imagination here, lol. Just kidding.
i would say if the COG is above or bellow the rockers, the body would roll without putting any additional force in the heave spring, assuming the wheels don't slide laterally.

[ringo]

And the answer is?

Now that we are discussing the heave spring, how programmable can these get, as it relates to progressive springs, and multiple springs on the shock.
The heave spring, being much bigger and less compact has an advantage in being able to package more technicalities than the torsion bars.

The technical regulations are very loose with the suspension. It is only required that the suspension moves as a function of wheel displacement alone.

It may not be against the rules to tie the front to the back, or have a progressively stiff ARB as well.

[riff_raff]

Cars with underbody aero devices don't like the pitch changes that occur when braking. Pitch changes due to braking cause a shift in the aero CofP and upset the balance front-to-rear. So these cars like a suspension that is stiff in pitch. But with regards to roll, a super soft suspension will keep all of the tires in contact with the track while braking or accelerating in a corner. That's why the third spring was added to F1 and Champ car chassis.

With the very refined mass distribution, suspension geometries, and optimized composite suspension and chassis structures in F1, it may be the case that the additional roll stiffness provided by having a dedicated spring at each corner is not necessary. A mono spring linkage will weigh less, take up less space, will be stiffer with lower inertias, and will be more consistent with set-up due to a fewer number of potential variables.

Of course, you should take my comments with a grain of salt. I'm a transmission guy, not a chassis guy.

riff_raff

[marcush.]

You can use the move of the cop to your advantage if you are able to control it ,though.
It is nothing else than movable ballast .If you put a big bullet in the trunk of your car it will not benefit the behaviour but if you would be able to place the bullet were you need it at a fingersnip this will help the dynamical behaviour of your machine.(assuming the total weight is a given ,and we are not adding weight
by ballasting the car-of course we do but only to reach the minimum allowed weight).

[autodoctor911]

[/quote]

someone accused the carbon tube in this picture as acting as the ARB in this setup. obviously, a carbon fiber tube this diameter would have a high enough resistance to torsion to not allow any usable roll movement. It took a few minutes trying to figure out what the heck the transverse silver Ohlins damper was doing to realize that in roll, the whole rocker tube assembly moves laterally, so there must be a spring or two inside the pivot housings on each side to control roll stiffness.

Back to the subject matter though:
how have they interconnected the front and rear in F1? is it hydraulic like the rally car systems that are now banned, or have they combined the front and rear linkages in a similar way to the way a 3 spring or monospring setup does the left and right?

I think ya'll are missing something on the point of moving the roll stiffness from corner springs to the ARB. When a corner spring is resisting roll, it only places a force on it's corner, where as the ARB is applying an equal force on each side, in opposite directions. I am just going back to basic tuning principals. whenever you increase the diameter of an ARB to reduce body roll, the tire on the inside of the turn is lifted more, reducing traction at that corner, where as if you instead increase the spring rates to reduce body roll, less weight is transferred to the outside tire.

[DaveW]

I think ya'll are missing something on the point of moving the roll stiffness from corner springs to the ARB. When a corner spring is resisting roll, it only places a force on it's corner, where as the ARB is applying an equal force on each side, in opposite directions. I am just going back to basic tuning principals. whenever you increase the diameter of an ARB to reduce body roll, the tire on the inside of the turn is lifted more, reducing traction at that corner, where as if you instead increase the spring rates to reduce body roll, less weight is transferred to the outside tire.

Without thinking about it too much.... I suspect the sprung mass (chassis) in your thought experiment is fixed in space.

[Jersey Tom]

When a corner spring is resisting roll, it only places a force on it's corner, where as the ARB is applying an equal force on each side, in opposite directions. I am just going back to basic tuning principals. whenever you increase the diameter of an ARB to reduce body roll, the tire on the inside of the turn is lifted more, reducing traction at that corner, where as if you instead increase the spring rates to reduce body roll, less weight is transferred to the outside tire.

Completely untrue. Adding roll stiffness on an axle, be it by spring or ARB... the result in pure cornering is the same. Roll stiffness is roll stiffness. Adding it by one way or another, you'll be increasing load on the outside tire and decreasing it on the inside tire.

An example of where it DOES make a difference is with a single wheel ride input. By introducing a direct spring connection between the inside and outside wheels, if one has a bump input it will be directly transferred across the axle... whereas with springs some of that is delayed and absorbed through inertia (the input has to go through the sprung mass).