Serpent S400 Product guide

SETUP BOOK

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CONTENTS
INTRODUCTION 3
BASIC SETUP 4
1. CASTER 4
2. TOE 5
3. DOWNSTOPS 6
4. SHOCK ABSORBERS 7
5. TRACK WIDTH 9
6. RIDE HEIGHT 9
7. CAMBER 11
8. ANTI-ROLL BARS 12
9. SUSPENSION TWEAK 13
10. DIFFERENTIAL ADJUSTMENT 15
All texts and images contained within this booklet are copyright of Serpent MRC ©2007

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2INTRODUCTION
Setting up a racecar with fully-independent suspension,
like your Serpent S400, is necessary to make the car
perform well. We have developed these straightforward
procedures to help you set up your car properly and easily.
Always follow these procedures step-by-step, in the order
presented, and always make sure that you make equal
adjustments on both left and right sides of the car.
These section describes the default settings for your
Serpent S400.
Setup Order
We have determined that you should set up your S400 in
the order indicated in the table below. The order of the
settings has been determined as the most logical to set up
your S400 properly and easily. Also, certain settings must
be made before others, as changing one setting will impact
another setting.
The table below gives you a breakdown of what components
need to be attached on the car, and what you will need to
measure the settings.
For example, to set the downstops:
· Detach the shocks.
· Detach the anti-roll bars.
· Remove the wheels.
· Use a setup system (downstop blocks & gauge)
· Use a at board.
(-/+)
(-)
(+) Attach or use this component / apparatus
DO NOT attach or use this component / apparatus
Component / apparatus may (+) or may not (-) be attached or used.

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BASIC SETUP
This section describes the default settings for the Serpent
S400 and how to adjust those settings. We strongly
recommend you thoroughly read this section so you
understand how the settings are adjusted.
The setup described here is a good starting point. After
rebuilding the chassis, or in case you become lost with your
setup, always return to the setup described here.
If you choose to adjust the settings to better suit different
track conditions, make small adjustments, one at a time,
and see if you nd any improvement in handling with each
adjustment. We advise you to keep track of your setup
changes, and record which setups work best at different
racetracks under various conditions.
1. CASTER
Caster is the forward/rearward angle of the front steering
block with respect to a line perpendicular to the ground.
Initial Steps
None
Setup Apparatus
None
1.1 SETTING FRONT CASTER
To change front caster you must change the C-hubs to
those of different caster values.
IMPORTANT!
You must use matched caster
blocks (same caster angle) on
both left and right sides of the
car.
Front Caster Default= 4º
To change the front caster
setting, replace the installed
caster blocks with those of the
proper caster angle.
2° 4° 6°

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42. TOE
Toe is the angle of the wheels when looked at from above
the car.
· Wheels parallel with the centerline of the car
have a toe value of 0°.
· Wheels that are open toward the front have a
negative toe value (toe-out).
· Wheels that are closed toward the front have a
positive toe value (toe-in).
Setup Apparatus
Measure and adjust front and rear toe using a setup system
on a at reference surface
IMPORTANT!
Make equal adjustments on both left and right sides of the
car.
2.1 MEASURING TOE
Measure front and rear toe using the setup system
according to the instructions provided with the setup
system.
2.2 SETTING FRONT TOE
Front Toe Default Setting = -0.5° (toe-out)
Adjust the front toe-out value
of each front wheel to –0.5°
(fronts of front wheels pointing
outward) by adjusting the
lengths of the front steering
rods.
· To set less toe-out,
LENGTHEN each steering
rod equally.
· To set more toe-out,
SHORTEN each steering
rod equally.
2.3 SETTING REAR TOE
Rear Toe Default Setting = +3.0° (toe-in)
The rear toe is adjusted by using different suspension
brackets at the front and back of the rear bulkheads.
The default setup uses a 0º bracket at the front, and the 3º
bracket at the back.
(These two brackets are included in the kit.)

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3. DOWNSTOPS
Downstops limit how far the suspension arms travel
downward (which determines how far upward the chassis
travels).
Downstops are a primary setup adjustment that affect other
setup adjustments.
IMPORTANT!
Make sure you adjust downstops equally on both left and
right sides of the car.
Initial Steps
A. Shocks: It is not absolutely necessary to remove the
shocks, however you must be sure they are long enough
not to limit the suspension travel. Be sure the suspension
is reaching the downstop limits before the shocks are
fully extended. Also ensure that there is not an excessive
amount of preload on the shocks, or the downstop values
may appear to be lower than actual.
B. Front anti-roll bar: Disconnect one ball-joint from the
front anti-roll bar
C. Rear anti-roll bar: Disconnect one ball-joint from the
rear anti-roll bar.
D. Wheels: Remove the wheels from the car.
Setup Apparatus
Check downstops using a downstop measuring set and at
reference surface
3.1 MEASURING DOWNSTOPS
Using the measuring gauge, measure the distance from
the reference surface to the lowest point of the front/rear
suspension arms.
· Positive numbers on the
gauge indicate the distance
(in mm) ABOVE the top
level of the elevating blocks
(or, above the bottom of
the chassis).
· Negative numbers on the
gauge indicate the distance
(in mm) BELOW the top
level of the elevating blocks
(or, below the bottom of
the chassis).
3.2 SETTING FRONT DOWNSTOPS
Front Downstop Default Setting = + 3mm
Set the front downstops so the bottoms of the lower
suspension arm are at +3mm on the gauge.
(Actual measurement = 3mm above top level of elevating
blocks, or 1mm above the bottom of the chassis).

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6Adjust front downstops by turning the front downstop
setscrews into or out of the front suspension arm.
· To increase the front
downstop value, turn IN (CW)
the front downstop setscrews
INTO the front suspension
arm.
· To decrease the front
downstop value, turn OUT
(CCW) the front downstop
setscrews OUT OF the front
suspension arm.
IMPORTANT!
Make sure you adjust front downstops so they are equal on
both left and right sides.
3.3 SETTING REAR DOWNSTOPS
Rear Downstop Default Setting = 4mm
Set the rear downstop screws so the bottoms of the rear
suspension arms are at +4mm on the gauge.
(Actual measurement = 4mm above top level of elevating
blocks, or 4mm above the bottom of the chassis).
Adjust rear downstops by turning the rear downstop
setscrews in or out of the rear lower arms.
· To increase the rear downstop
value, turn IN (CW) the rear
downstop setscrews INTO the
rear suspension arm.
· To decrease the rear
downstop value, turn OUT
(CCW) the rear downstop
setscrews INTO the rear
suspension arm.
IMPORTANT!
Make sure you adjust rear downstops so they are equal on
both left and right sides.
4. SHOCK ABSORBERS
Shock absorbers, or shocks, are the suspension
components that allow the wheels to keep as much contact
as possible with the track surface. The Serpent S400 has
fully-independent front and rear suspension, meaning that
the suspension at each corner of the car (front left, front
right, rear left, rear right) moves and may be adjusted
independently of the others. As such, there is a shock
absorber at each corner of the car.

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Damping, mounting position, spring tension, and spring
preload are all characteristics that determine how the
shock performs. The shock absorbers of the S400 must be
disassembled to change the shock oil and pistons in order
to alter the damping.
Initial Steps
A. Shocks: To adjust shock damping, remove the shocks
from the car by unscrewing the upper and lower shock
pivotballs. You do not need to disconnect the shocks to
adjust spring preload (for ride height adjustment).
Setup Apparatus
None
4.1 ADJUSTING SHOCK ABSORBER DAMPING
To adjust shock absorber damping, disassemble the shocks
and change the pistons or shock oil.
· To get softer damping, use a piston with more holes
or use thinner shock oil.
· To get harder damping, use a piston with less holes
or use thicker shock oil.
The standard setting for the S400 shocks is using a 3-hole
piston and 500cst shock oil
4.2 SETTING THE FRONT
SHOCK ABSORBERS – UPPER
MOUNTING POSITION
Front Shock Default Upper
Mounting Position = 2nd
HOLE FROM TOP
Attach the front shock upper
pivotball to the 2nd hole from
the top on the front shock tower.
4.3 SETTING THE FRONT
SHOCK ABSORBERS – LOWER
MOUNTING POSITION
Front Shock Default Lower
Mounting Position = OUTER
HOLE
Attach the front shock lower
pivotball to the outer hole on the
front lower suspension arm.
4.4 SETTING THE REAR
SHOCK ABSORBERS – UPPER
MOUNTING POSITION
Rear Shock Default Upper
Mounting Position = 2nd
HOLE FROM TOP
Attach the rear shock upper
pivotball to the 2nd hole from
the top on the rear shock tower.

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84.5 SETTING THE REAR
SHOCK ABSORBERS
– LOWER MOUNTING
POSITION
Rear Shock Default Lower
Mounting Position = MIDDLE
HOLE
Attach the rear shock lower
pivotball to the middle hole on
the rear lower suspension arm.
5. TRACK-WIDTH
Track-width is the distance between the outside edges of
the wheels, front or rear. It is important that front and rear
track-widths are adjusted symmetrically, meaning that the
left and right wheels (at one end of the car) must be the
same distance from the centerline of the chassis.
On a car with C-hub suspension the track-width is typically
not adjustable. But by using different wheel-hexagons with
different widths or by changing to different suspension
brackets, the car’s track-width will change as well.
When using the parts that come with the kit the S400 has a
track width of slightly less than 190mm.
Initial Steps
A. Shocks: Attach front and rear shocks.
B. Wheels: Mount all four wheels on the car.
Setup Apparatus
Measure track-width with the
car resting on a at measuring
surface or a at setup board
which has graduated markings
to measure track width.
5.1 MEASURING TRACK-WIDTH
Measure front track-width on the outside edges of the front
wheels.
Measure rear track-width on the outside edges of the rear
wheels.
6. RIDE HEIGHT
Ride height is the distance between the bottom of the
chassis and the reference surface on which the car is
resting. Adjust ride height with the car ready-to-run but
without the body.

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Initial Steps
A. Shocks: Connect front and rear shocks.
B. Anti-roll bars: Disconnect front and rear anti-roll bars.
C. Wheels: Mount a set of wheels/tires or mount our set-
up wheels
Setup Apparatus
Measure ride height with the
car resting on a at reference
surface (such as a at setup
board).
6.1 MEASURING RIDE
HEIGHT
Measure the ride height from
the very end points of the
chassis at the front and rear of
the car, using calipers or a ride
height gauge.
6.2 SETTING FRONT RIDE HEIGHT
Front Ride Height Default Setting = 5mm
Adjust front ride height by increasing or decreasing the
preload on the front shock springs.
· Increase front ride height by tightening the spring
preload collars on the front shocks (increasing the
preload).
This moves the collars DOWN the shock bodies.
· Decrease front ride height by loosening the spring
preload collars on the front shocks (decreasing the
preload).
This moves the collars UP the shock bodies.
6.3 SETTING REAR RIDE HEIGHT
Rear Ride Height Default Setting = 5mm
Adjust rear ride height by increasing or decreasing the
preload on the rear shock springs.
· Increase rear ride height by tightening the spring
preload collars on the rear shocks (increasing the
preload).
This moves the collars DOWN the shock bodies.
· Decrease rear ride height by loosening the spring
preload collars on the rear shocks (decreasing the
preload).
This moves the collars UP the shock bodies.
IMPORTANT!
Make equal adjustments on both left and right sides at each
end of the car.

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10 7. CAMBER
Camber is the angle of a wheel to the surface on which the
car is resting (with wheels and shock absorbers mounted)
when looked at from the front or rear of the car.
· Zero degrees (0°) of camber means the wheel is
perpendicular to the reference surface.
· Negative camber means that the top of the wheel is
leaning inward (toward the centerline of the car).
· Positive camber means that the top of the wheel is leaning
outward (away from the centerline of the car).
Initial Steps
A. Shocks: Connect front and rear shocks.
B. Anti-roll bars: Disconnect front and rear anti-roll bars.
C. Wheels: If measuring camber using a setup system,
remove the wheels and following the instructions included
with the setup system. If measuring camber using a camber
gauge, mount the wheels and set the car on a at reference
surface.
Setup Apparatus
Wheels on:
Measure camber using Serpent’s Camber Gauge #1460 and
a at reference surface (such as a at setup board).
Wheels off:
Measure camber using a setup system and a at reference
surface.
There may be differences in measurements depending on
whether you measure camber using a camber gauge or a
setup system. The reason is that tires (especially the rear
tires) have a tendency to lay at on the reference surface.
If this happens (that is, if the tires are not pre coned),
the camber readings may differ as much as 0.5° from the
reading you would get with a setup system.
7.1 MEASURING CAMBER
Measure the camber using the camber gauge or setup
system. Before measuring camber, lift and drop the end
of the car (front or rear) a few cm’s to let the suspension
settle.

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7.2 SETTING FRONT CAMBER
Front Camber Default Setting = -2.0°
Set the front camber to –2.0° (top of front wheel leaning
inward).
Adjust front camber using the
upper camber link attached to
the front C-hub.
· To get more negative
camber (more slanted),
shorten the front upper
camber link.
· To get less negative
camber (more upright),
lengthen the front upper
camber link.
IMPORTANT!
Make equal adjustments on both left and right sides of the
car.
7.3 SETTING REAR CAMBER
Rear Camber Default Setting = -2.0°
Set the rear camber to –2.0° (top of rear wheel leaning
inward).
Adjust rear camber using the
upper camber link attached to
the rear upright.
· To get more negative
camber (more slanted),
shorten the rear upper
camber link.
· To get less negative
camber (more upright),
lengthen the rear upper
camber link.
IMPORTANT!
Make equal adjustments on both left & right sides of the
car.
IMPORTANT!
After you set the camber, re-check the ride height settings.
Camber and ride height settings affect each other, so be
sure to check each one when you adjust the other.
8. ANTI-ROLL BARS
Anti-roll bars are used to adjust the car’s side traction and
alter chassis roll.
Initial Steps
A. Anti-roll bars: Connect the front and rear anti-roll bars.
Setup Apparatus
None

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8.1 SETTING THE FRONT ANTI-ROLL BAR
Default Front Anti-roll Bar= RED anti-roll bar
Adjust the front anti-roll bar by
replacing the anti-roll bar wire
with another wire of different
thickness.
· Thinner wire = softer front
anti-roll bar
· Thicker wire = stiffer front
anti-roll bar
8.2 SETTING THE REAR ANTI-ROLL BAR
Default Rear Anti-roll Bar= YELLOW anti-roll bar
Adjust the rear anti-roll bar by
replacing the anti-roll bar wire
with another wire of different
thickness.
· Thinner wire = softer rear
anti-roll bar
· Thicker wire = stiffer rear
anti-roll bar
9. SUSPENSION TWEAK
A “tweaked” car is an unbalanced car, and has a tendency
to pull to one side under acceleration or braking. Tweak is
caused by an uneven wheel-load on one particular axle. You
should check for suspension tweak after you have set up all
other suspension settings.
Initial Steps
A. Shocks: Connect the front and rear shocks.
B. Anti-roll bars: Disconnect the front and rear anti-roll
bars (initially).
C. Wheels/Tires: Mount a set of wheels/tires. Ensure that
each set of left/right tires is the same size.
Setup Apparatus
Measure tweak with the car sitting on a at reference
surface
CHECKING FOR REAR TWEAK
Determine if the REAR of the car is tweaked by checking at
the FRONT of the car.
9.1 Lift and drop the front end and rear end of the car a
few cm’s to let the suspension settle.
Soft Med. Hard

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9.2 Place a sharp tool
underneath the front
end of the chassis at its
middle point, and lift
the front end.
If one front wheel lifts
before the other, the
rear end of the car is
tweaked and may be
adjusted by rear spring preload.
9.3 Adjust the preload on the
rear springs until both front
wheels lift at the same time.
Increase the preload on the
rear spring diagonally across
from the front wheel that lifted
rst, and decrease the preload
on the rear spring diagonally
across from the front wheel that
lifted last. Adjust both rear springs in equal but opposite
directions, otherwise you will change the rear ride height.
9.4 Reconnect the rear anti-roll bar, and check for rear
tweak again by lifting the front end of the car.
If one front wheel lifts before the other, the rear anti-roll
bar is tweaked. Adjust the length of one or both rear anti-
roll bar linkages until both front wheels lift at the same
time.
CHECKING FOR FRONT TWEAK
Determine if the FRONT of the car is tweaked by checking
at the REAR of the car.
9.5 Lift and drop the front end and rear end of the car a
few cm’s to let the suspension settle.
9.6 Place a sharp tool
underneath the rear
end of the chassis at its
middle point, and lift
the rear end.
If one rear wheel lifts
before the other, the
front end of the car is
tweaked and may be
adjusted by front spring preload.
9.7 Adjust the preload on the
front springs until both rear
wheels lift at the same time.
Increase the preload on the
front spring diagonally across
from the rear wheel that lifted
rst, and decrease the preload
on the front spring diagonally

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14 across from the rear wheel that lifted last. Adjust both front
springs in equal but opposite directions, otherwise you will
change the front ride height.
9.8 Reconnect the front anti-roll bar, and check for front
tweak again by lifting the rear end of the car.
If one rear wheel lifts before the other, the front anti-roll
bar is tweaked. Adjust the length of one or both front anti-
roll bar linkages until both rear wheels lift at the same time.
10. Differential Adjustment
Differentials allow the wheels at opposite ends of the same
axle to rotate at different speeds. Why is this important?
When a car turns in a circle, the outer wheel has a larger
diameter circle to follow than the inner wheel, so it needs to
rotate faster to keep up. If the differential is too tight, the
result is that the wheels “ght” each other for the proper
rotation speed; the result is a loss of traction. Generally, the
more grip a track has, the tighter the diff action should be.
The S400 features a ball
differential in the rear and a
solid axle (spool) in the front.
Optional available is a front
differential as well as a one way
axle.
Setup Apparatus
Serpent diff-adjustment tool
The most important thing to adjust on a ball differential is
the pressure that is applied to the internal diff balls. The
pressure should be high enough to drive the car forward
without letting the diff pulley slip between the diff plates. To
check the diff tightness, place the diff tool into the slots in
the two diff outdrives, and then try to turn the pulley. You
should not be able to turn the pulley, or at the very least it
should turn only when you apply extreme force.
· If the diff is too loose (pulley turns too easily), apply
more diff preload by tightening (CW) the adjusting
screw.
· If the diff is too tight, the balls and shims are more
easily damaged. In that case you should reduce the
diff preload by loosening the adjusting screw (CCW).

#401002 - Version 1
Serpent Model Racing Cars BV
Spaarneweg 12E, 2142 EN, Cruquius
The Netherlands, Europe