Sponsored

rubi takeoff suspension vs. LCA

txj2go

Well-Known Member
Joined
Apr 7, 2020
Threads
34
Messages
1,219
Reaction score
1,244
Location
DFW
Vehicle(s)
CTS-V, 2018 JLU Sport Firecracker Red
I have the Rubicon takeoff parts and I've been doing research on the installation. What I don't understand is why the LCA needs to change if you only change springs and shocks. I understand what caster is and I understand how the geometry changes when you lift the suspensioni, but what I don't understand is how the Rubicon gets away with the same LCA as the sport when it is effectively lifted the same amount. IOW why doesn't the Rubicon require a different LCA with its stock springs and shocks? Take them off of one frame, put them on an identical frame without the decal on the hood, and the geometry is different? Is there a difference in the mounting points on the axle that makes the difference?
Sponsored

 

daveprice7

Well-Known Member
First Name
Dave
Joined
Aug 26, 2019
Threads
12
Messages
633
Reaction score
867
Location
Junction City, OR
Vehicle(s)
2019 Sport 2DR, 2020 Willys 2DR
Occupation
Nerd
My understanding is that Rubicon caster is on the low side from the factory, but "in the acceptable range"... Plus, folks tend to try and find springs for a heavier configuration to use in the swap, which gives more lift and lowers the caster more than a factory Rubicon.

I put 4dr Rubicon springs on my 2dr Sport, and while they were one or two steps lower than the tallest Rubicon springs, I got about 1.75" of lift from it (maybe a bit more than that in the back, as my Sport was low in the back before and now rides a bit high in the back). I can't really tell the difference in caster after the swap, so I'm in no rush to change the LCAs. Maybe some people are just more sensitive to it than me, or it's more obvious at speeds I don't usually drive.
 

Headbarcode

Well-Known Member
First Name
Mike
Joined
Aug 16, 2018
Threads
26
Messages
7,782
Reaction score
17,829
Location
LI, New York
Vehicle(s)
2019 JLUR Stingray 2.0 turbo
Vehicle Showcase
1
I have the Rubicon takeoff parts and I've been doing research on the installation. What I don't understand is why the LCA needs to change if you only change springs and shocks. I understand what caster is and I understand how the geometry changes when you lift the suspensioni, but what I don't understand is how the Rubicon gets away with the same LCA as the sport when it is effectively lifted the same amount. IOW why doesn't the Rubicon require a different LCA with its stock springs and shocks? Take them off of one frame, put them on an identical frame without the decal on the hood, and the geometry is different? Is there a difference in the mounting points on the axle that makes the difference?
The lca's and their frame and axle mounting points are identical in all models. They get the caster right in the comfort zone on the Sports and Saharas, but are barely toe nailing the minimum range on the Rubicons. Many stock height Rubicon owners have switched to the .25" longer lca's from the Mopar lift, to get their caster into the comfort zone. Proper caster eliminates wandering.

The more parts that cross over, the less cost is involved in providing different models.
 
OP
OP

txj2go

Well-Known Member
Joined
Apr 7, 2020
Threads
34
Messages
1,219
Reaction score
1,244
Location
DFW
Vehicle(s)
CTS-V, 2018 JLU Sport Firecracker Red
I was thinking that all of the parts were identical except the springs/shocks. As I wrote my first post I realized that the AXLE is different and if all of the details were followed through with during design they could have designed the Rubicon axle to have slightly different mounting points for the control arms to use the same control arms but get the right caster. Apparently they didn't do that so now I understand the situation.
 

Sponsored

limeade

Well-Known Member
First Name
Guy
Joined
Oct 29, 2018
Threads
30
Messages
1,478
Reaction score
2,777
Location
Reno, NV
Vehicle(s)
2018 JLUR
Vehicle Showcase
1
Like @Headbarcode stated, get yourself a pair of the Mopar lift LCA's when you install the Rubicon suspension. Your caster will be very similar to what your Sport has now.
 

entropy

Well-Known Member
Joined
Sep 19, 2018
Threads
83
Messages
4,318
Reaction score
7,442
Location
Foothills of the San Gabriels
Vehicle(s)
Jeep Wrangler Sport S JL 2-D
Build Thread
Link
Occupation
Professional dancer/male stripper
I understand what caster is and I understand how the geometry changes when you lift the suspensioni, but what I don't understand is how the Rubicon gets away with the same LCA as the sport when it is effectively lifted the same amount.
It doesn't get away with it. Rubicons have shitty caster from the factory. If you don't install the longer LCA you will have the same shitty caster rubicons have. If you install longer LCA, you'd have better caster.
Sponsored

 
 



Top