05-20-2005, 12:20 AM
Will be going with 315's on the rear and eibach pro kit. Im afriad it might sit too low for the 315's. Has anyone ever used these instead of replacing the springs?
06-04-2005, 10:59 PM
Check my post here:
The rubber spacers tend to have about half the effect as the metal ones.
06-07-2005, 12:45 AM
any info on how spacers in general affect spring rates/ hadling of car
06-07-2005, 12:54 AM
(good info on similar thread)
06-07-2005, 09:57 AM
any info on how spacers in general affect spring rates/handling of car
Ahhh, in this question you ask how spacers can effect the RATE. Yes they can. Just like cutting the coils can effect the spring rate.
One one hand, I like being one of the few to have this info, but I guess I'll share cause I like helping you guys so much.
Ok, lets use the stock rear spring as an example. It is a linear rate 115lb per inch spring with about 8 coils total (I'm rounding off). As a side note, there are 2 factory springs with the same height and rate, just a different number of coils. Wierd, huh?
Anyway, first I should mention how spring rates are measured. The 115lb rate means that it takes 115lbs to compress the spring 1 inch, 230lbs total to compress it a total of 2 inches etc... Make sense? This is a linear rate in that it doesn't change. Progressive rate springs will change rate due to the way they are wound. More info on those is in this thread:
The coils on each end are compressed and are mainly used to hold the springs in place. They are considered the "dead" coils as they do not contribute to the load bearing duties. Only the 6 "active" coils are actually doing the work. So we take the 115 and divide by 6. We now see that each coil is responsible for 19.1666lbs (or 20 if we use round numbers).
So for instance, if we cut off one complete coil, the springs new rate will be 20lbs higher or 135lbs per inch.
Or, if we instead add 2 metal spacers, 180* apart in the middle of the spring we are essentially making one complete coil "dead". The effect on spring rate is the same 135lbs per inch.
The only difference in these 2 techniques is that one way lowers and one way raises the ride height.
Doing both will make the rate 155lbs per inch and keep the ride height about the same.
Cutting half a coil or using one metal spacer will have half the effect or increase the rate to 125lbs per inch.
It's pretty simple. Keep in mind that rubber spacers will compress and tend to have half the effect of the metal spacers (assuming they are both the same size). There are different rubber densities as well among the different companies that make them.
Things get a little more complicated when dealing with progressive rate springs and then there are differences in where spacers are placed in the spring and other things that are hard to explain. I won't go into detail on that, but hopefully this will be helpfull to you guys.
Let me know if you have any more questions.