This is related to adjustable coilovers and shocks.......
Original question:
Bob's request for more information:
Requestor's reply:
Bob's answer/reply:
Since most spring rates are quoted in hundreds of pounds instead of thousands, I went to the Skunk2 site. I could find springs listed in hundreds of pounds, but not thousands. Maybe people who say they have those "6K" and "8K" springs could tell us the spring rates and educate us.

If a MFG has "6 thousand pound" springs for a car that weighs about 1/3
of that, there is something here that I sure don't understand as to what would push it onto the road with that kind of force.

Generally a spring's purpose is to support the weight of a car and keep it from bottoming out. Stock springs were engineered/designed to support the weight of a car, so I believe spring rates close to stock do what they were designed to do if a car is street driven. I believe heavier shocks
and lighter wheels keep the tires in contact with the road longer during bumps and depressions.

In a racing application such as a banked turn, the car will "weigh" more than stock as it is pushed down into the banking by cornering forces, so heavier springs than stock are needed to keep the car from bottoming out.

In a racing application such as a car getting airborn, the car will "weigh"
more when it lands, as it is pushed down into the pavement by an "increase" in gravity, so heavier springs than stock are needed to keep the car from bottoming out.

If I were driving on a banked track or one where the car becomes airborn,
I would calculate what the car weighs sitting still, and what I believe it will weigh on the banking and/or landing, and that would tell me the spring rate I would need to keep the car from bottoming out. That is why I asked about car weight and stock spring rates.

I asked about the forces that will be trying to push the car into bottoming out mode for the same reason.

As for a street driven car, I would go with spring rates close to stock since they were engineered/designed to support the weight of a stock car. and use heavier shocks to damp out the road bumps and depressions
to keep the tires pushed down onto the road, regardless of the minor ups and downs of the car's body while being driven on the street.

Everyone has a right to their own opinion, but I believe springs that are
too hard, cause a car to lose grip in a turn, since I believe hard springs
don't allow the tires to follow the road contours as closely.

Since I cannot figure the forces that a person will encounter on the street
in EACH turn, or even the radius of EACH turn encountered on the street,
It's pretty hard to say for the street, exactly what springs, other than stock, that a person should use.....especially in flat Florida, where the steepest bank is the X-way entrance/exit.

I suspect that life being full of compromises, most people have what they think they need instead of what they really need. They are also limited by how much they want to spend, and don't keep buying springs until they get the "feel" that they want.

With a race car, a person has several sets of springs and tunes for each
track going harder or softer.....the advantages are: 1.Race turns and radiuses won't change for a given track, so they can be measured. The street is a multitude of compromises and variables and most people won't keep buying springs until they get it right for their type of driving.
2.Driver preference and driving style remain constant/flat out on a race track but on the street, a person is not always driving at the limit of his ability.

Does anyone here care to tell us what they are using, and if they could change it, which way they would go?.......-Bob