[Goshe]

Turn rings down raises the car up. Initial spring rate the same but gets stiffer than before as it reaches suspension stops or bottoms out because of increased spring compression. So car does get stiffer as it approaches the end of it's travel. If you're worried about coil bind do the math on the gaps compared with the shock shaft left or better yet go with a dual rate system and dial in the ride.

 

[Goshe]

Sorry but this is not the case, the spring rate of a liner spring does not change throughout the entire compression cycle. What you describe is a progressive spring in which the spring rate increases with the compression cycle.

Something to consider which has not been addressed is the motion ratio. If the motion ratio changes through the suspension travel it will effectively change the effective spring rate. One would need to model the suspension geometry to check for ratio change through movement. Sorry but it's not that important and this is not NASCAR 🤷‍♂️

For every inch you compress the spring you increase the resistance force. The more you compress the spring the more resistance force is applied. It's at the end of the travel you notice the spring change more than the beginning.

 

[Goshe]

Adding preload doesn’t compress the spring, it extends the shock and increases ride height.
Linear springs do not change rate anywhere in their compression. They only change the resistive force.

Think about it it raises the vehicle but you're turning the rings down so at the end of compression there is more spring compression therefore more resistance.

 

[Goshe]

That's not how a linear spring works. I think you are confusing compression force with spring rate. Spring rate does not change on a linear spring no matter how far it's compressed.

Spring Rate (performancetrends.com)

What are linear springs and how do they work? (motioncontroltips.com)

I shouldn't have used the word rate, my bad it's force that I'm referring to and how the ride will feel stiffer.