2nd installment on Spacer lifts on Fakebook

[tommudd]

Simple....

It doesn't.

I know this argument has and will go on forever, but physics is physics.

My KJ has 209k miles on it, and sat at 18.5" fender measurement, so I also don't understand the "sagging" I read about ALOT. LOL.


And just a lil tidbit, an internal spacer, or an external spacer does not "change the spring rate". Springs are rates in how many pounds of force it tacke to compress the spring one inch. A 350# spring takes 350 # of force to compress it, but that's when its manufactured. Of course there are tolerances, and fatigue that come into play.


Pre-loading with an internal spacer seems to me would reduce the total travel, and make it feel "stiffer" when it takes a hit.

Yes physics is physics and it does in fact change the spring rate and amount of travel you have.
Your last line is right in that it makes it stiffer, hence the changes spring rate
In the end spacer lifts are bad in all ways
As far as sag, yours has sagged so what do you not understand?

 

[Jschulte]

From what I've read, factory was approximately 19". But I've read lots of threads saying they sagged 1.5" or more, with lots less miles, some saying like 50-60k miles. With mine having over 200k, it's odd that mine was still @ 18.5"



I come from a solid axle background of nearly 30 years, so PLEASE excuse for for not completely understanding ifs, but I'm pretty mechanical, and hard headed... LOL!!!!


As far as spring rates, please correct me when f I'm wrong. A 350# spring takes 350# to compress one inch, 700# to compress 2 inches, 1050# to compress 3" and so on.... so with a 2" internal spacer it already has 700# of pressure on it.
BUT, it still only takes another 350# to compress another inch. This is not
"Changing the spring rate". It's still 350#, it just requires 1050# to compress the next inch... but since the KJ doesn't quite have 1050# per corner, it seems very stiff. I do realize that leverage in the control arms has an effect here, but it still would SEEM stiffer, even though the rate hasn't changed.

 

[tommudd]

From what I've read, factory was approximately 19". But I've read lots of threads saying they sagged 1.5" or more, with lots less miles, some saying like 50-60k miles. With mine having over 200k, it's odd that mine was still @ 18.5"



I come from a solid axle background of nearly 30 years, so PLEASE excuse for for not completely understanding ifs, but I'm pretty mechanical, and hard headed... LOL!!!!


As far as spring rates, please correct me when f I'm wrong. A 350# spring takes 350# to compress one inch, 700# to compress 2 inches, 1050# to compress 3" and so on.... so with a 2" internal spacer it already has 700# of pressure on it.
BUT, it still only takes another 350# to compress another inch. This is not
"Changing the spring rate". It's still 350#, it just requires 1050# to compress the next inch... but since the KJ doesn't quite have 1050# per corner, it seems very stiff. I do realize that leverage in the control arms has an effect here, but it still would SEEM stiffer, even though the rate hasn't changed.

I have lifted quite a number of KJs, Most all were about an inch of sag at 70,000 miles or so , my 03 when I picked it up at 78,000 was almost sagged 1.75 inches. Had one 05 with 79,000 that rolled into my garage having almost two inches, stock tires ( 235-70-16s ) were rubbing.
So possibly someone has replaced your springs since I have never seen one with that many miles not sagged some at least.
My 05 with 98,000 now is sagged 3/4 of an inch on stock suspension. My 04 I bought new never sagged since I dumped the crappy stock suspension at less than 20,000 miles.
NOW since you want to get technical we can
while no it does not change the " SPRING " rate it does in fact change the way it reacts to going down the road over bumps etc . That effectively changes the way it handles it to "ACT " like a heavier spring. ( when of course using a spacer lift )
We can discuss this all day, been doing it since the 1970s and have upgraded 100s and 100s of trucks/ cars/ 4x4s etc

 

[tjkj2002]

From what I've read, factory was approximately 19". But I've read lots of threads saying they sagged 1.5" or more, with lots less miles, some saying like 50-60k miles. With mine having over 200k, it's odd that mine was still @ 18.5"



.

Depending on what year your KJ is the stock height could have been 20"+.

 

[forcefed44]

Simple....

It doesn't.

I know this argument has and will go on forever, but physics is physics.

My KJ has 209k miles on it, and sat at 18.5" fender measurement, so I also don't understand the "sagging" I read about ALOT. LOL.


And just a lil tidbit, an internal spacer, or an external spacer does not "change the spring rate". Springs are rates in how many pounds of force it tacke to compress the spring one inch. A 350# spring takes 350 # of force to compress it, but that's when its manufactured. Of course there are tolerances, and fatigue that come into play.


Pre-loading with an internal spacer seems to me would reduce the total travel, and make it feel "stiffer" when it takes a hit.

I have actually seen the RC in person and can't knock it. You only have a choice with those spacer things for the front.. Either RC or top spacers.. Other than that go full suspension setup.

 

[tommudd]

I have an OTT from RRO, and an RC here just to show people what not to use and why :gr_grin: