FJ Cruiser 3" Suspension
Lift Post Install Review and Observations
Here's a little insight that I came to realize after installing my
Rough Country 3" Suspension Lift on my 2010 FJ Cruiser. Take
it for what it's worth. Note, I'm not an expert but I am
willing to experiment and think through problems. If you find
this info useful, let me know and happy wheeling!
I have a 2010 Toyota FJ Cruiser. I put the 3" RC lift with the
rear springs on my FJ and shortly after during a long highway drive,
I noticed a degraded difference in the handling of the FJ Cruiser.
I did plenty of research into what may be causing this and came up
with a few theories. One theory I put to the test with some
NASCAR derived suspension adjustments.
What I discovered was that the stock front springs
are not the same spring rate as the new Rough Country rear springs.
It is possible that the shocks may be stiffer and that is what I am
feeling but the result is an effect on handling and tracking
straight. For instance, driving straight, hit a dip or a bump in the
road on one side and the FJ will wander one way or the other. Or
sometimes when steering, it's easier to over-steer. I felt like I
was constantly correcting. Braking hard, the front would dip or dive
as some people call it. Overall it now tended to wander and
occasionally pull to one side or the other on un-even roads or if I
encountered mild bumps or dips in the road. Not exactly what I
expected or really desired.
I thought about this for a while. I know a little something about
suspensions, angles, spring rates and shocks. There were two
possibilities. One possibly reason is when the A-arm suspension is
raised on the FJ, the castor changes. Look at the plane that the
upper A-arm rotates in and as that arm moves down, the upper ball
joint moves forward, thus reducing the castor angle by a few
degrees. This would affect handling. A few companies sell
replacement upper control arms that adjust castor and add a few
degrees of negative castor, tilting the axis rearward at the top
again, closer to the stock position.
Another possible reason is spring rates and shocks. For springs
there is a difference in spring rates from stock to after market.
With shocks there is a difference in new Rough Country rear shocks
to OEM rear shocks. This sets up an imbalance between rear shocks
and the stock front struts. When I drove fast over a speed bump is
when I noticed the distinct difference. The front springs / struts
were soft. The rear springs / shocks were stiff. Having been a
NASCAR fan years ago, I knew of ways to quickly make an adjustment
that would affect spring rates. So I used something called a spring
rubber, which in my case was a small rubber cylinder foot or post
used for supporting machines. I used wire ties to hold this rubber
piece in between the coils of the front strut. This stiffened the
strut's spring rate. There was an immediate improvement in handling.
What does this tell me? The Rough Country 3" lift that replaces the
rear OEM spring sets up an imbalance in the suspension from front to
rear. The rear suspension is stiffer than the front. This in turn
affects handling. By placing a spring rubber in the front strut
spring and stiffening the spring rate, it became more "balanced"
from front to rear and handling improved.
So what's my suggestion? If you intend to go with Rough Country or
any other suspension system that is similar (there are several of
this style out there), then keep the OEM rear springs and go with
the spacer in the rear. The fact that you may keep the rear
OEM springs may mean for a better balance suspension, but I'm not
sure about that. Alternately, buy a lift that replaces the
strut springs, such as Old Man Emu. But do your research and ask
others about the springs they chose based on the setup of their FJ
Cruisers (type of terrain they travel on, weight distribution, winch
bumpers, winches, etc). Old Man Emu sells several different spring
rates that lift the FJ a maximum of 3". This is not an
endorsement for Old Man Emu, I just know they sell springs of
varying rates. By the way, 3" is about the maximum you can raise the
A-arm type suspension without over arching the stock a-arm angles.
Otherwise for a taller lift, a sub-frame lift is necessary. The key
is to match the rear spring rate with the front spring rate to
balance the suspension. This is also dependent on how much weight
the FJ carries up front and at the rear and what type of ride
quality you want (stiffer, softer). Personally I like a slightly
stiffer ride on the road with tighter cornering stability. But not
too stiff that I jam my backbone.
As far as shocks and struts go, a lifted FJ will usually get a new
rear shock to add more shock travel. If this rear shock is built for
offroad as most lift kit shocks are, it will be stiffer than stock
and the rear shock will be stiffer than the OEM front strut. Softer
front, stiffer rear will cause handling changes. For instance the
front may feel like it dives during braking, or the front corners
may dip in a sharp turns causing a "loose" feeling and over-steer.
How do you address this? Stiffer strut springs will help. So will
completely new after-market struts built for offroad. In my case, a
simple test using a spring rubber that stiffened the spring rate
helped, though I don't want to make that a permanent solution.
Ultimately I'll probably buy Old Man Emu springs after I buy a new
front winch bumper and a new winch since that added weight will call
for a stronger front spring. Well, live and learn. The
least I can do is share my thinking.