4
TUNING & SETUP TIPS
0° mount,
0° mount,
0° mount,
0° caster
2° caster
4° caster
2 shims forward
1 shim each side
2 shims to rear
This section explains the adjustments possible to
tune your front end for different track conditions.
CASTER
describes the angle of the kingpin
when looked at from the side of the car. As an ex-
ample, 0° of caster puts the kingpin in a vertical
line. Positive caster means the kingpin leans rear-
ward at the top. Increasing the positive caster on
your car will slightly increase the steering turning
into a corner and slightly decrease steering com-
ing out of the corner. Reducing the positive caster
will decrease the amount of steering you have go-
ing into a corner and increase the amount of steer-
ing you have in the middle of the corner and exiting
the same corner.
Your car has adjustable caster in increments
of 2°. With the 0° upper arm mounts you can have
settings of 0°, 2°, and 4° of positive caster as shown.
You change the caster by placement of the PTFE
caster shims on either side of the upper arm mount.
The three drawings below show the locations of
the caster shims and what the resulting caster set-
tings will be.
For greater amount of caster than moving the
upper arm caster shims, you can add the #4127
REAR
caster spacers under the suspension arms. They
come in 2° increments. Be aware that adding these
caster shim spacers will change your ride height.
#4127 shims
(optional)
FRONT SUSPENSION SPRINGS
are available in various wire
sizes as listed at right. Changing springs will increase or decrease steering. In
general a softer spring (smaller wire diameter) will add steering and a harder
spring (larger wire diameter) will decrease steering. Oval racing will nor-
mally require a harder spring than road course racing.
CAMBER
is a word describing the angle at
which the tire and wheel rides relative to the ground
when looked at from the front or back. This is one
of the most important adjustments on the car. Nega-
tive camber means that the tire leans inward at the
top, putting it closer to the centerline of the car
than the bottom of the tire. Positive camber means
just the opposite, the top of the tire is further away
from the centerline of the car than the bottom of
the tire.
TOE-IN AND TOE-OUT
is a beneficial
adjustment and has a fairly significant effect on the
car. Toe-in will help stabilize your car and it also
removes a small amount of turn in steering. Toe-
out will allow the car to turn in to a corner quicker
but will cause instability exiting the corner or on
bumpy tracks. Both toe-in and toe-out will scrub
speed so try to use as little, of either, as possible.
You adjust the toe-in or toe-out by adjusting the
length of the steering tie-rod turnbuckles.
Excessive
negative camber will decrease
traction but increase stability. Positive camber will
do the same. We suggest a starting setting of 2° of
negative camber. Try to use at least 1 to 2° nega-
tive camber at all times and make adjustments to
keep your tires wearing flat. This can be adjusted
by turning the upper arm turnbuckles in the appro-
priate direction.
Part Number
Wire Size
#8433
(.024")
Harder (less steering)
#8431
(.022")
#8429 (kit std.)
(.020")
#8427
(.018")
Softer (more steering)
CASTER CHANGE
The 0° mount is level with the chassis when
mounted. The 10° mount is angled 10° in relation
to the chassis or lower suspension arm. This angle
provides a change in caster during suspension
movement. The caster angle will change two de-
grees during full suspension travel. Your car will
steer more aggressively when using this option. The
starting or static caster setting is changed in the
same manner using the PTFE caster shims. Static
caster starts at either 2°, 4°, or 6°. A more detailed
example would be a starting caster of 2° will have 0° caster at full suspension travel and a starting caster of
6° will be only 4° at full suspension travel. This setup is recommended for road racing applications, giving you
the most aggressive steering possible.
REAR
10° mount,
10° mount,
10° mount,
2°-0° caster
4°-2° caster
6°-4° caster
2 shims forward
1 shim each side
2 shims to rear
