Coilovers vs lowering springs

[Bryce]

Greg,

You are right. I was saying you order the right springs but the weight of the car was 50 lbs heavier/lighter than you planned for. The car sits a 1/4" too low or too high. You could adjust that back to correct. Sometimes you can only get a spring rate to the nearest 25lbs.

This is what I use to determine spring rates:

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When I choose spring rates I do (two) calculations.

First what is the weight of the car at that axle. Divide that number by 2. this gives you F (force or weight)

Since F=kx next is to determine the amount fo droop you want or the shock has. This amount of droop gives you the minimum preload on the spring at ride height. If you have 3" of droop you dont want the spring to become unloaded. take F/x=K. K is your MAXIMUM spring rate.

Now this is where personal preference comes in. I design around a 1G bump. How much travel do you have in your shocks from ride to full compression, this is your x for the next equation. Take F times 1G, or whatever number you want to design around. F/x=K this is you MINIMUM spring rate. Now you have a range.

The only way to adjust this is to adjust your shock length and your shock length at ride height.

[GregWeld]

Yes Bryce --- you're right of course....

1/4" or even a bit more.... but you're post might lead a guy to believe he could crank the car up or down an inch or more maybe.... since you didn't mention the "1/4". An INCH up or down in a coil over is way too much - as you know.

Many people just don't understand how little a coil over actually travels... and you start dropping a coil over an inch - and you could be bottoming out. This gets worse as a guy is trying to correct for a wrong spring rate/length.

When I post here (on Lat G) I try to make sure that ANYONE reading the posts is getting the right info because there's so many people reading without commenting etc... That is NOT to say I know what I'm talking about... and I get corrected often by people with far more knowledge than me. I try to post from my perspective - which is many years of fixing many of these very (Vari? LOL) issues on my own cars as well as those of my friends.