OK thanks. Actually, BC does not stand for buddy club - it is a BC racing product shown below. It has no helper springs to confuse the issue for me. linky

 

12k is about 672 lb per inch, i am running 12k front and back on my daily s2k. I cant say it's too stiff or not since it's a personal thing(with other factors like condition of the road, etc)

you might want to get a set of sway bar too, they only "kicks in" during a corner.

 

how much preload you need depends on how much travel you'll get before you ride bumpstop aka near infinite k constant.(and lenth of damper)

your car is about 2800 so 700 a corner(50/50 wd), with a 12k spring your spring will lower/compress about inch(and a tad more) at rest, if you have a damper with 3 inch travel, 1/3 of your stroke is already gone with the MG of the car at rest.

i preload my 12k spring about an inch in front and 7/8 in the back, to tell you the truth the ride around town actually feels a tad better(relative term), high speed bump is more control, i think at some point i was riding the bumpstop before(with no preload)

I just gotten the alignment done, let's see if time improve in SOW next time.

 

Why were you riding on bumpstops before preload? Maybe we have a different defintion of preload.

If I had fully adjustable coilovers, even without preloading the spring, if you just lowered it using the lower perch (turn the whole body of the shock shorter)....the spring/suspension travel would be full travel.

Unless your 12k spring is really really short, you shouldn't have to actually preload the spring much at all. I'd leave it where it was from out of the box.

You'd be riding the bumpstops if you UNLOADED the springs enough. Like if you just turned the spring perch way down to slam the car or something.

Preload in my definition means putting the spring perch so that the spring has no movement (car in the air)..and then crushing the spring some more.

Unloading means that the spring is free to move around up and down (with the car in the air) and the shock has to compress before it meets the spring when you put the car down.

This means that even if the spring is not preloaded (not unloaded either), the car would only push down on it about 1'' since it weighs around 700lbs/corner. With the spring at rest and the shock at full extension, I'd hope you had much more than 1'' of shock travel before you bump stopped.

 

um..not really. =P

The length of the spring is not even half as important as how much stroke the damper has(before it wacking the bumpstop), on my set up i have about 3inches at full droop.
like i said with the car on the ground it will compress about 1 inch(700 a corner at 672lb/inch)

after calculating the k constant and corner weight, i have about 2 inch of damper trave, 2 inch for me is border line not enough, someone using them on the street might never use the full stroke but at the track i feel like i am running low on the damper stoke(uncomfirm at this point, will update you once i go to the next event)

My set up doesn't have helper spring nor it's a progressive unit, let me know if my math is not right.

i know what you mean by preload to a point the spring doesn't upseat at full droop, that's my definition of neutral preload aka a little bit just to keep it seated right.

cliff: 3 inch of damper travel at full droop(aka car on the jack stand), 2 inch of stroke with the car in normal on the ground, unknown inch of travel at hard corner. again, that's my take of it.(which could be completely wrong)

 

a bit more reading from the race forum guy

cliffnote: autox guy runs 10k spring with 1inch+preload to keep it off the BS

 

Myself and Rdizzle were speaking on behalf of the Buddy Club Race specs and maybe others. All this talk of pre load vs spring/ride hight and damper travel has no relevance to these coilovers because they are fully adjustable and independent of one another with these adjustments, so there is no compromises in how you want to set these settings up, you can slam them and run any pre load you want and still have the same damper travel unlike some other dampers. Don't know what your going to get with "BC" but don't confuse our BC RS abbreviations for "BC" coilovers, I believe these are a lesser performing set up for the money.

Pre loading the springs is part of the tuning tools we have at our disposal-- if you pic the right coilovers that utilize this feature separate from the other set up features, such as ride height and damper travel etc. Coilover and suspension set up you could say is an art, but it is also very much a science, pre load I wouldn't say is really a "black art", understanding what its primary purpose is will be key, once this is understood you can use it effectively for what it was intended and also manipulate it to perform other task to help aid in compensating for some other handling attributes that may be lacking. Its primary function is to increase the amount of force it would take to compress the spring, (but only on its initial hit), it will not increase the strength or stiffness throughout the full springs stroke -- just the initial movement, (the amount of force is applied to move the spring from its resting point) Once the spring has moved, it is at the same rate strength no mater what the preload setting is adjusted to. It is not the same as simulating adding a stiffer rate spring from say a 10k to now a 12k. This is how a "strait rate" spring works with pre load. I believe most drop springs and full coilover springs are "strait rate" so this info is most relevant.

A progressive spring will have some "ramp up" when spring pre load is applied, but still not the same as moving up to the next stiffer spring weight, also how the progressive spring is wound will also determine how pre load will effect it. Make sense?


So I will provide one example of this pre load usage for you to help in understanding how it can work for you in a positive way and one in a negative -- first since more spring pre load will take more energy to now compress the "initial" stroke of the spring, it can add in decreasing body movement in a fast maneuvering situation much like the role of stiffer sway bars -- adding more direct and quicker feedback, "more response and less body roll" this can be done front and rear or just rear or just front depending on what handling character you are trying to archive. A negative attribute of spring pre load if done excessively will be poor wheel fallowing to irregular road surfaces, this as you know will creating traction issues such as braking bumps etc. Every car will be different in its component list and related susp set up and so will driver preferences, so it is important to understand what each one of these related components job is and what it can and can't do, then you can maximize what ever you have. For me I run no pre load in the rear and about 5 full turns up front. This is for several reasons which I will spare getting into for now.

 

This is a prime example of using pre load for a secondary use other then its first intended purpose which is never going to get you the best results possible from your susp. This is a situation where a stiffer spring would be required. More compression damping or stiffer sway bars could also be an alternative, though can sometimes create their own inherent negative attributes in other situations, but hitting the bump stops in any situation is going to be far the worst case scenario, so optimally increasing the stroke will yield the best results by allowing you to place all the other settings, damping/ spring weight etc to be at its optimal placement so that the susp can perform its best without compromise ideally.

 

opps totally forgot about the link!

https://www.s2ki.com/forums/index.php?showt...0&#entry1739855



preloading a tad works best for me, which in no way i am saying it's the golden rule of anything