If someone would be so kind as to explain the proper use of the third spring,I would appreciate it.

My understanding is that it is used to compensate for the downforce generated by the wings. Which allows the use of softer springs at the wheels. I may be wrong and have never attempted to adjust it.

So if anyone knows please help.

Interesting - my understanding is a bit different.

As the third spring (being central) does not get used in cornering, it can be made suitably soft to look after bumps, the amount of pitching, and (with its damper) the rate of weight-transfer during braking and acceleration.

This allows the wheel springs to concentrate on cornering, allowing them to be made STIFFER for lower average ride height, lower body roll and less camber effect.

To me what you say wouldn't work as downforce will just compress whatever is easiest (path of least resistance) which would be your softer wheel springs.

Hmmm, I like your explanation Jonty.

I will look into 3rd springs some to see what I can find. I must admit complete ignorance to 3rd springs.

I'd like to know more about it myself. I've been basically setting it to about what my wheel springs are set at. But, I suppose it should be looked at as a fulcrum for shifting weight...softer means the weight transfer will be slower and harder means it will be faster and more pronounced.

All I know about it is what it does to the car between it being hard and soft. Too much oversteer and I need to soften it. If I need it to rotate better, I raise the spring rate. There. I let out 1 of my secrets! BTW, this is obviously only with open-wheel cars. And just my amateur observation.

Found this on Atlas F1...

"The third spring is mainly a "late activate spring" loining in basic idea RDV's set up with soft springs and bump rubbers.

At low speed, low downforce and softer spring better mechanical grip.
Problem comes with maintaining a sufficient ride height at higher speed when the downforce is trying to crush the car on the ground.
Soft spring can lead to dynamic ride height too low at higher speed and such reduce downforce or even car sitting on the ground in the worse case.

A 3rd spring is a typical application for high downforce cars.
It is an attempt to use soft spring for low speed and higher rate at higher speed when the suspension compress under the aero load.

RDV is doing the same with his bump rubber set up. The main difference in these 2 solutions is that 3rd spring correctly fitted will not impact the roll while the solution used by RDV will.
The 3rd spring solution will comparatively use harder roll bars than the bump rubber set.

Additionally you can use the 3rd spring to limit pitch variations and add a damper on it you can control the speed of mass transfer under braking or acceleration in a certain extend without altering the single wheel damping over bumps.

The main problem remaining are the transition phases.
I've been using 3rd springs for some time and is one of the key points: don't be in the transition phase in middle of corners or your suspension rate won't be constant and generaly drivers don't really like this
But this problem also exist with the bump rubber set."

And in english please.....

3rd spring only comes into play when both sides of the suspension move the same direction(either up or down), at the same time. Ie: when the aero downforce is trying to make the bottom of your F1 car merge at a molecular level with the asphalt. :)

Very easy to test. Go to a high downforce track, make 3rd spring as soft as possible, and max out the wings. Watch the replay when you go down the longest straight, I guarantee you'll shoot enough sparks out the bottom to rival The Rose Bowl fireworks show on 4th of July.

In setup terms: the 3rd spring allows you to adjust how the car handles over severe bumps or under extreme downforce. So if you make 3rd spring harder/stiffer, you can keep the car from bottoming out (make it harder for the downforce to squish down your suspension), while leaving your normal springs/dampers softer to get better mechanical grip when cornering the car.

However, making the 3rd spring too hard can cause the car to skip over bumps in the track, and make the car unresponsive/lockup under hard braking.

Third springs effectively decouple longitudinal spring forces from latitudinal roll spring forces.

I usually set my front third spring to "smooth" and my rear third spring to "stable".

Steve Wood

Posted by Steve Wood at 06:44 PM on Jun 29, 2008 Post #4

I'd like to know more about it myself. I've been basically setting it to about what my wheel springs are set at. But, I suppose it should be looked at as a fulcrum for shifting weight...softer means the weight transfer will be slower and harder means it will be faster and more pronounced.
.

Steve, it's actually the opposite. Softer means weight transfer will be faster.
Softer 3rd spring/dampers = easier to compress/decompress the 3rd spring = when braking in a straight line, the front nose dips violently, back end comes up quickly.