Quote Originally Posted by lil_foy View Post
Wouldnt having it uncaptured at full extention mean on the chance that when you're at full extention (for example on the inside tyres of a high G corner) you have "x" amount of unloaded compression when the weight gets shifted back. Which wouldn't be ideal, yes?
Yep you're right, there would be shock travel and body roll before the spring contacted the perch where the spring would have no influence and that corner of the car would effectively be in free fall (except obviously the compression damping of the shock and bushing stiffness would be acting as spring rate). Alternatively though if the shock is droop limited, as in the situation where you have a heavily "preloaded" spring, then you will have the same problem except instead of continuing in droop travel the shock will just stop and lift the tyre of the ground abruptly and contact the ground just as abruptly as the cornering load is removed. Neither situation is desirable in my opinion.

However this will very rarely happen on tarmac with swaybars, as it is very difficult for a shock to reach full drop under cornering loads on a smooth surface assuming the single wheel rate of the sway bar is sufficient to overcome the unsprung mass trying to pull the wheel down toward the ground. If you are rallying or in dukes of hazzard style situations where you are hitting full droop constantly, then keeping the spring captive with a helper spring or similar is definitely advisable.

Sorry if my explanation is a bit poor, I prefer to draw things on paper .

Quote Originally Posted by senna View Post
The biggest issue you will have when a coil becomes untrapped is that it can move from the locating seat and potentially damage the shock rod or body when the coil is compressed again in this position.

Pre-load is a stupid term when it comes to coilovers, think of it this way - wind the spring seat up, wind the spring seat down what have you changed? The position of the spring, that is all. The weight on the coil is still exactly the same! If you wind up the "pre-load" on the coil you are simply bringing the spring closer to the installed or loaded height, the closer you are to loaded height, the less droop or down travel the shock has then negating the rebound effort of the shock. Once you have little or no rebound stroke you will also experience less tyre contact with the road making the car skittish and handle worse.

The only reason the spring seat is adjustable on those coilovers is to allow different length coils to be used on a one size fits all shock body and also you can try and set the coilovers up so that once at ride height the shock has the ideal amount of stroke in bump and rebound.
Great post. Succinctly sums up the main concepts on why preloading is just tuning the amount of bump and droop travel.

Quote Originally Posted by Oxer View Post
http://s3.amazonaws.com/kym-assets/photos/images/newsfeed/000/184/961/tumblr_lnvvueuSsj1qcj56b.png?1318394475



Actually, If you wind a spring up, beyond the point of where contact to the top plate it, and continue to wind it up, you are "Loading" the spring. A spring doesnt just compress and the rate stays the same, the rate will change as it is under a lot more force then it it was not "Loaded" therefore the ride would become quite a bit stiffer and more bouncy.

The term "Pre-Load" is only stupid to people who think they know how suspension components work.


Everyone is an expert in here though. Thank god for E-mechanics/E-engineers.
No I am not kidding. Plenty of shocks do not limit droop travel, which is what you are doing when you "pre-load" your spring, the world doesn't end and they don't have springs lifting off spring seats during use or shock shafts getting bent because of it.

I don't know how else to state this: senna and I are correct, you are wrong. A linear spring is linear (sorta, the geometry of the ends and a few other effects make them somewhat non-linear) and by compressing (preloading) the spring further when the shock is at full droop you are only limiting the amount of droop travel. The spring's rate doesn't change. I am not trying to be a dick but from reading your posts I don't think your understanding of suspension components is as good as you think it is. I can draw some diagrams to illustrate, or maybe we can just meet up at the next Ozhonda meet to discuss or something .