ok so im in the process of upgrading from 4.5 to 6.5 I pulled my old rustys 4.5 spring out. The new RC spring is the same height as the rustys but its supposedly 6.5 lift. The rustys spring has more coils then the RC spring can that be right? I checked the part number on the box and it comes back a 6.5 inch spring help me!

 

rough country doesnt have 6.5 leaves. they do 4.5 with 2 inch shackles

 

X2 on that...Tj

 

He's talking about coils. They are probably the same height but sounds like the RC coil is much stiffer with more coils to it, thats were they get the extra 2" from

 

the spring rate has nothing to do with the lift. the thickness of the steel and number of coils is what gives lift

 

X1

 

actually a higher rate can lift the truck... just look at the guys that use FORD f150 springs in the front... the spring is shorter than stock BUT it is WAY thicker and has a WAY stiffer spring rate... so YES spring rate has a LONG to do with the lift

 

Rusty's spring run a 150lb spring rate and RC IICR is a 212lb spring rate. they will get you to 6.5"

 

here the rc spring clean on verse rustys dirty one

 

0-2 on this thread, nice work

spring rate definitely plays into ride height. not to mention that thickness of the steel is related to spring rate. definitely not the whole story, but there is a relation

your rustys spring has the same length to get only 4.5" because they are masters at putting inferior products into production.

 

really? i talked to grimus yesterday... they do not do 6.5 full packs

 

um...yes. because we again, are talking about coils. and yes rate has to do with lift.
if there is 1000lbs over the front axle and it takes 500lbs to compress the spring one inch, in theory it will compress 2 inches. (well split it with 2 springs) if they take 1000lbs to compress 1 inch then they will be compressed one inch, and at the same free height, make the vehicle sit one inch higher. I know this isnt exact but it makes my point.
so in short, run them. dont worry so much. take pics.

 

makes sense thanks guys

 

Spring length is only 1 factory indetermining lift height. My 3.5" lift spring are 1/2" shorter than the stockers. But they are thicker wire and more turns, higher spring rate. Same can be said of leaf springsLay 2 springs side by side and 1 could have a 6" arch and 1 a 7" arch. that does not mean the 7" arch set will give more lift. If it is lower spring rate it very well could be a shoerter lift spring.

 

kinda like how my 3" rear spring is only 1.5" taller tan my stocker... but I still got a solid 3" lift (slightly more to be honest)