The low-down on RE spring rates.

[XJoachim]

Eagle, look at the picture above of my rig. Does that look like a stiff spring? :roll:

 

[CRASH]

yes, the spring rate is inversely proportional to the # of coils, so if you cut a spring in 1/2, the coils are reduced by 1/2 and the spring rate is doubled.

If someone could measure the wire diameter, spring diameter, the uncompressed length, and the # of coils, i could calculate the spring rate for you all. let me know.

-J

I'll do that as soon as I get my springs.....should be tomorrow.

Still no call from PORC, so we'll have to do the calculation method.

CRASH

 

[Eagle]

They are a lot longer spring and will give you the 7.5 lift, you have to remember that the spring rate is based on compressed inches so every inch that they are compressed the rate increases 200lbs

SPOBI!

Spring rate is spring rate. Unless the coils bind, the rate is constant. It does NOT increase as the spring is compressed.

 

[Willis]

Considering that OEM springs are around 180 and Rusty's have been reported to be about 160, 250 does sound a bit stiff. Factory heavy duty rears back in the 80s were 220 and I think the fronts probably match that fairly closely. I have OEM HD spings in my original '88 and I don't care for them. They haven't sagged at all in 240,000 miles but they ride harsh and I'm going to replace them with 2000 Up Country coils.

250 sounds good. The problem is, most of us have added stiffer rear springs, and if you have soft front springs, the rear dictates the attitude of the vehicle, you end up with a 'stiff cricket' and not a balanced setup. Ideally, you want the front and rear suspensions working close to equally.

James Duff has a variable rate coil I'd like to get information on. They have 2 different hights, a 2" and a 4" for early Broncos. I want to figure out how much lift they will give an XJ, and what the overall rate is.

Steve

 

[79yj]

16 mm diameter and 132 mm wide coil
just over 5/8" diameter and just less than 5 1/4" wide coil
under winch and bumper load they measure just a hair under 18.5 tall.
On a side note, they feel mushy when driving around town.
7.5 springs I think not! Seems more like 6 or 6.5 inches of lift.
I am running 6" Rustys rear pack and a 1.25 shackle in the rear. I can see at least 1 1/2" less up front, looks like I am slamming on the brakes.
I am not happy with them.

 

[Mike L]

Btt

To bring this back up since no one has confirmed what the actual spring rate of the 7.5 spring vs. the 4.5 ZJ spring.

-Mike