Coilover Adjustment

Have a question from last nights Intro to Alignment Webinar.

We discussed how to properly set the ride height, and how the bottom collar is really for the total length of the component and suspension travel, not for ride height.

I believe I understand how lowering the ride height via the upper collar would work. My confusion comes from the pretension.

If you lower the spring collar down to lower the ride height. Would the spring float between the collar and the top retainer? How do you both lower the ride height and manage pretension with a single collar?

The older style 'coil-over' with a single threaded adjuster for the, usually, bottom of the spring is indeed primarily adjusted to ensure the spring is held securely in place between the top and bottom collars. If more preload is used, it will lift the vehicle as the pring platform has been raised, but it will also limit the extension of the spring under light loading, which can affect the tyre loadings and cause the vehicle to be twitchy at that point.

It is possible to lower the spring platform, but this will require a 'helper', spring to avoid unseating the spring in it's seat - this is a special, very low spring rate, secondary spring that's intended to close fully (coil bind) under light loading, leaving the rest of the travel under the control of the main spring. There are springs available that actually have two spring rates - the main one and a very soft one that replaces the 'helper' spring.

Normally, though, the ride height is adjusted by swapping in a shorter spring, or a longer one to raise the ride height.

This should help a lot more than anything I say - https://suspensionsecrets.co.uk/helper-springs-and-tender-springs-the-difference/