Performance Springs FAQ

Q: How do I install an adjustable coilover kit?

A: There are 2 ways for this step, either bolt on or weld on.

The process is very simple. There are 2 ways to install them. Before

you install coilover springs, you need to make sure you have stronger

aftermarket struts installed. For more information about how to install

insert struts in your rear, see the Suspension FAQ.

Method 1: If you would like to keep your original spring perch location, you can simply unscrew the top screw of your insert strut and slide the collar on. This would require a very short collar, or you will not be able

to screw the top screw back on top. If you have collars that are too

long then they will need to be trimmed. Pictured below is a Ground

Control kit that comes with very short collars. Your range of height

adjustment will be very small. The good news is that if you are using

the original spring perch, it won't drop your car down too much anyway.

Finally you must secure the collar so that it is not loose based on the

instructions of the manufacturer.

Method 2: The proper way to do the installation is to have the original

spring perch machined off, and having the new collars welded on. This

will also keep you away from possible rattles from loose suspension parts.

It would be ideal in this situation to get longer collars so that your range

of adjustment will be greater. Of course you can't go down too far with-

out having to remove the original brake line tabs.

After either method 1 or 2 is performed, it's a matter of putting the

top spring holder (hat) on top, and bolting on your original strut top.

Some hats have a hole that is too small for the strut rod to go through.

In this case you will have to drill or machine it out to size. Also pictured

below is a finished product using the weld on method. (MR2 pictured)

Spring Rates and Drop Height

We offer the spring rates for comparison between brands, also as helpful information when choosing custom spring rates. Spring rate figures are in lb/in domestic figures, to convert to kg/mm international, divide figure by 56. If there are 2 values listed, that means that the spring starts at one rate, and ends at another rate under full load. There are some conflicting figures for stock, based on source, and location, so if you have any missing or correct information please email.

Brand Front Rear Drop (In)
Stock1 140-168 112 0
Stock2 123 106 0
Stock JDM 134 140 0
TRD 224 202 0
PI (UK) 224 112 1.5
Brand Front Rear Type Drop (In)
Stock (< 10/91) 174 162 Progressive 0
Stock (> 10/91) 123 168 Progressive 0
TRD (Street) 224 218 Progressive 0
TRD (Lowering) 224 218 Progressive 0.79
TRD (Rally/Dirt) 240 184 Linear 0
SARD 174-252 118-252 Progressive 1.4
TEIN H 235 162 1/1.2
INTRAX Progressive 1.5
A'PEXi 300 212 1
Whiteline 175 135 Linear 1.5
Good Coilover Rate (Street) 550 350 Linear 1-3
Good Coilover Rate (Race) 750 500 Linear 1-3


TEIN H 1.4-5.8 1.2-5.3