User Manual

SLAYER PRO 4X4
•
37
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 38, 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 38 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:
#5359 Progressive 3 Rocker Arm Set
#5133 Pushrod Spacers (these are required to lengthen the pushrods to
maintain proper suspension travel.)
The chart below demonstrate the effect of the various rocker arms
on wheel force as the
suspension is compressed.
On the progressive rate,
wheel force is light at
first and increases as the
suspension is compressed.
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
Constant
Rate Travel
Wheel Travel
Wheel Force
0
2
4
6
8
10
12
14
16
18
20
10 20 30 40 50 60 70 80 90
Progressive
Rate Travel