Different kinds of coilovers
 

I noticed that there are 2 main types, one like Ohlins that can be height adjusting without changing spring preload, and another one like KW that can be height adjusted via spring preload.
What are defects and advantages of both types?
I know that in second type, lowering will reduce excursion.

The advantage is exactly as you've outlined- being able to control ride height separate from the spring pre-load. I think the only disadvantage to adjusting them separate is that you're intruding more adjustments, which is more complex.



Think of it like buying a rifle without a scope, vs buying a rifle with a scope. Yes, the gun will still shoot and function without a scope. Adding the scope with allow you to dial in your aim properly though, but adds complexity in that it's one more setting you have to adjust.


Adding a scope = Separate pre-load adjustment

Check this out.



https://www.youtube.com/watch?v=eRJ9V8rSpwc

In this specific case Ohlins has the separation of preload from ride height because they’re travel limited (as most monotube shocks), and most coilovers with that system suffer from that.
The disadvantage of the spring perch adjustment is what you already know, but in the case of Kw’s which are twintube it’s not a big problem unless you run too much low/high ride heights outside of the range. In both cases you will have other problems before you’re even near of the maximum/minimum.
Other big factor is spring rate, the more you run stiffer springs the less travel problems you will end up with, generally with low spring rates you need as much travel you can get.

Almost always a cost saving measure that has been marketed as an important feature.

You'll notice most very high end shocks do not have separate ride height and preload.

It can be a good thing to have if you know how to use it and it's designed right, but that is uncommon.

A few more details:
https://www.instagram.com/p/B9J1M8Un..._web_copy_link
https://live.staticflickr.com/65535/...10c75ca5_w.jpg

- Andrew

Height independent coilovers tend to have shorter shock travel (shorter stroke, less distance until bottoming out).