36 • SLAYER PRO 4X4
This advanced tuning guide will take you one step further into the
cutting edge technology that has been designed into Slayer Pro 4x4.
Follow the instructions provided here to take advantage of Slayer Pro
4x4’s maximum performance potential.
SUSPENSION AND ALIGNMENT SETTINGS
Caster Adjustment
The caster angle of the front
suspension may be used to adjust
the understeer (push)/oversteer
handling characteristics of the
model. Generally, increasing the
caster angle will move the truck
towards an oversteer condition
(more traction on the front tires, less
on the rear tires). Decreasing the
caster angle will create a tendency
towards understeer (pushing in the
turns). From the factory, the front
suspension is set to a caster angle of
10-degrees. The rear caster angle
is not adjustable. The caster angle
of the front suspension can be
adjusted from 5° to 15°. Adjust
the caster by positioning the
caster adjustment shims on the
upper control arms of the front
suspension as shown in the table
to the right.
Caster Angle, and Bump Steer
Bump steer is unwanted change in the steering angle of the front
wheels as the suspension travels up and down. It can result in unstable
and unpredictable handling. Bump steer is affected by the position of
the outer toe link end on the axle carrier. From the factory, the toe links
are positioned so that bump steer is virtually eliminated. When the
caster angle is changed, the outer toe link end should be repositioned
on the axle carrier to maintain zero bump steer geometry. Adjustment
is achieved using the shims and hollow balls provided with the vehicle.
Refer to the Bump Steer Elimination chart on page 37, and look up your
caster angle setting to find the correct position for the outer toe links.
Positioning the front toe-links correctly will maintain the original factory
geometry and eliminate the unwanted steering angle changes caused
by bump steer.
In the rear, a small amount of bump steer can be used for advanced
tuning. On smooth surfaces, having the rear wheels toe-in slightly
when the suspension is compressed can add stability during hard
acceleration. Refer to the chart on page 37 for proper settings. Stock,
the Slayer Pro 4x4 is setup to increase rear toe-in during acceleration.
Note that rear toe-out is not used.
Rockers (Progressive Rate/ Suspension Travel)
One of the most exciting aspects of Slayer Pro 4x4’s suspension is the
inboard shock (damper) arrangement that uses pivoting rockers to
translate vertical wheel travel into linear shock motion. The rockers can
be changed to increase the progressive rate of the suspension.
The progressive rate determines how much the force at the wheel
produced by the springs being compressed (wheel force) will vary with
suspension travel (or vertical travel of the wheel). On a progressive
suspension arrangement, the wheel force will increase at a faster and
faster rate as the suspension is compressed. It feels as though the
shock spring gets progressively stiffer the more you compress the
suspension. On a linear suspension arrangement, the wheel force
increases linearly as the suspension is compressed. The spring does
not feel any stiffer, even when the suspension is fully compressed. This
provides a very “plush” feeling suspension with seemingly bottomless
suspension travel.
There are two different rocker arm sets that are compatible with Slayer
Pro 4x4. Both sets will allow the wheel to travel a total of 60mm in
the vertical direction. From the ride height position, the wheel will be
able to travel 40mm in the upward direction (bump), and 20mm in the
downward direction (droop). The Slayer Pro 4x4 comes equipped with
the Progressive 2 rocker set, which offers a good balance of progressive
rate for predictable body roll, brake dive, and high-speed stability.
The Progressive 3 rocker arm set (available separately) uses a higher
progressive rate that will provide a firmer feel, reducing body roll,
brake dive and rear squat. Installation of the Progressive 3 rocker arm
requires the following parts:
Rocker Arm
Total Travel
Progressive Rate
Progressive 2
50mm
(35mm up / 15mm down)
Medium
Progressive 3
50mm
(35mm up / 15mm down)
High
Caster adjustment shims (2 front, 2 rear)
Vertical
Ground plane
10°
Caster
In Front of
Hinge Pin Boss
Behind Hinge
Pin Boss
5.0°
None
Four
7.5°
One
Three
10.0°
Two
Two
12.5°
Three
One
15.0°
Four
None
Number & Position of Caster Adjustment
Shims (Front Upper Control Arm)
ADVANCED TUNING ADJUSTMENTS
