iRacing FORD F-150 Toyota Tundra Chevrolet Silverado User Manual
- June 13, 2024
- iRacing
Table of Contents
**iRacing FORD F-150 Toyota Tundra Chevrolet Silverado User Manual
**
DEAR iRACING USER,
Congratulations on your purchase of a NASCAR Truck Series vehicle! From all of us at iRacing, we appreciate your support and your commitment to our product. We aim to deliver the ultimate sim racing experience, and we hope that you’ll find plenty of excitement with us behind the wheel of your new car!
Why race pick-up trucks? For starters, they’re arguably the most popular automotive vehicle in America, with upwards of 2 million new pickups sold every year in the United States. And they’re a blast to race, particularly the trucks of the NASCAR Truck Series. With 625 horsepower pushing their 3450 pounds around super speedways, ovals, short tracks and the occasional road course, NASCAR’s trucks are fun to watch and challenging to drive.
The following guide explains how to get the most out of your new truck, from how to adjust its settings off of the track to what you’ll see inside of the cockpit while driving. We hope that you’ll find it useful in getting up to speed.
Thanks again for your purchase, and we’ll see you on the track!
Introduction
The information found in this guide is intended to provide a deeper understanding of the chassis setup adjustments available in the garage, so that you may use the garage to tune the chassis setup to your preference.
Before diving into chassis adjustments, though, it is best to become familiar with the car and track. To that end, we have provided baseline setups for each track commonly raced by these cars. To access the baseline setups, simply open the Garage, click iRacing Setups, and select the appropriate setup for your track of choice. If you are driving a track for which a dedicated baseline setup is not included, you may select a setup for a similar track to use as your baseline. After you have selected an appropriate setup, get on track and focus on making smooth and consistent laps, identifying the proper racing line and experiencing tire wear and handling trends over a number of laps.
Once you are confident that you are nearing your driving potential with the included baseline setups, read on to begin tuning the car to your handling preferences.
GETTING STARTED
Once you load into the car, press the clutch and select 1st gear. Give it a bit of throttle and ease off the clutch pedal to get underway. This car uses an h-pattern transmission, but only requires the clutch pedal to get the car rolling and when coming to a stop in gear. To upshift, simply let off the throttle and select the next higher gear. To downshift, give the throttle a blip while selecting the next lower gear. Upshifting is recommended when the tachometer is fully illuminated in red at high RPM. If you downshift too early, or don’t blip the throttle sufficiently, the wheel speed and engine speed will be mismatched, leading to wheel hop at the rear and a possible spin.
LOADING AN iRACING SETUP
When you first load into a session, the iRacing Baseline setup will be automatically loaded onto the car. If you would like to try any of the other iRacing pre-built options, you may select it by going to Garage > iRacing Setups > and then selecting another option that fits your needs. Because this car uses slightly different chassis and body configurations on different types of tracks, it will be necessary to load a setup from the same track type to pass tech inspection. For example, a setup for Talladega will pass at Daytona, but likely will not pass at Bristol.
If you would like to customize the setup, simply make the changes in the garage that you would like to update and click apply. If you would like to save your setup for future use click “Save As” on the right to name and save the changes. To access all of your personally saved setups, click “My Setups” on the right side of the garage. If you would like to share a setup with another driver or everyone in a session, you can select “Share” on the right side of the garage to do so. If a driver is trying to share a setup with you, you will find it under “Shared Setups” on the right side of the garage as well.
Dashboard
The Nascar Craftsman Trucks are all equipped with the Spek Pro gauge system, which combines easy-to-read backlit gauges, warning lights, shift light, and a visual Pit Road Speed helper all into a very intuitive system.
DASHBOARD OVERVIEW & FAILURE LIGHTS
While the gauges for each manufacturer are laid out differently, all three trucks feature the same gauges and the same functionality.
FORD F-150
TOYOTA TUNDRA
CHEVROLET SILVERADO
Each Truck features a large tachometer in the center with five accessory gauges arranged across the dashboard. These five gauges consist of:
Water Temp: Displays the temperature, in °F, of the water in the engine
coolant system
Oil Temp: Displays the temperature, in °F, of the engine oil
Oil Pressure: Displays the pressure, in psi, of the engine oil flowing
through the oil system
Fuel Pressure: Displays the fuel pressure, in psi, of the fuel flowing to
the carburetor
Volt Displays:98 the voltage of the battery
Under normal operating conditions, these gauges will all display with a white back light for the Silverado and the F-150, and a blue back light in the Toyota Tundra. Whenever a gauge is displaying a value that is dangerous to the engine, they will begin alternating between their normal color and red, such as the Oil Pressure gauge pictured below:
LOW OIL PRESSURE WARNING
TACHOMETER
NASCAR does not allow the use of either a speedometer or a pit speed limiter, thus the pit road speed limit can only be followed by running a specific RPM in a given gear. To help the driver maintain proper pit road speed without having to look at the tachometer, the Spek Pro tachometer features Pit Speed lights, which illuminate either yellow, green, or red to show whether the vehicle is traveling too slowly or speeding on pit road. These lights are accurate to a track’s pit road speed limit only when the transmission is in 2nd Gear, and are set automatically when loading a track in the sim.
PIT SPEED INDICATOR
If the vehicle is below the pit road speed limit, the tachometer will
illuminate the speed lights in yellow, with 1 light being farthest from pit
road speed and all 7 being moderately slower than the pit road speed limit,
usually just a few miles-per-hour slower than the limit.
APPROACHING PIT SPEED LIMIT
As the vehicle’s speed approaches the pit road speed limit (but is not
exceeding the speed limit), the pit lights will turn green, with 1 green light
being the farthest from the pit road speed limit and 6 lights being just
underneath the pit road speed limit.
AT PIT SPEED LIMIT
When the vehicle is traveling at the pit road speed limit, the 7th light will
illuminate in green and the backlight color will change to green, illuminating
the entire gauge with a green light.
EXCEEDING PIT SPEED LIMIT
When the pit road speed limit is exceeded, the entire gauge backlight will
turn red and the speed lights will also change from green to red. Similar to
the other modes, 1 red light is just above pit road speed limit and each
additional light signals the vehicle is exceeding the speed limit. If the
vehicle continues accelerating after the 7th red light, all speed lights will
turn off and the backlight will return to its standard color.
SHIFT LIGHT
The tachometer is also equipped with a Shift Light mode, which turns the gauge
backlight to red. This is distinguishable from the pit road speeding mode by
the speed lights being off, and will be enabled just before the engine reaches
the rev limiter.
ADVANCED SETUP OPTIONS
This section is aimed toward more advanced users who want to dive deeper into
the different aspects of the vehicle’s setup. Making adjustments to the
following parameters is not required and can lead to significant changes in
the way a vehicle handles. It is recommended that any adjustments are made in
an incremental fashion and only singular variables are adjusted before testing
changes.
TIRE SETTINGS (ALL FOUR TIRES)
COLD PRESSURE
Air pressure in the tire when the car is loaded into the world. Higher
pressures will reduce heat buildup, but will provide better grip with higher
loads and higher speeds. Lower pressures will increase heat buildup, but will
provide better grip at lower loads and lower speeds. Cold pressures should be
set to track characteristics for optimum performance.
HOT PRESSURES
Air pressure in the tire after the car has returned to the pits. The
difference between Cold and Hot pressures can be used to identify how the car
is progressing through a run in terms of balance, with heavier-loaded tires
seeing a larger difference between Cold and Hot pressures. On left-turn ovals,
the right-front tire should always see the highest buildup on a balanced car,
while the left sides should be roughly the same, but it is important to
monitor the hot pressures after a run and adjust accordingly. Ideally, the
difference in hot pressures on one side of the car should be roughly equal to
the difference between cold pressures after a longer run.
LAST TEMPERATURE
Tire carcass temperatures, measured via Pyrometer, once the car has returned
from the pits. Wheel Loads and the amount of work a tire is doing on-track is
reflected in the tire’s temperature, and these values can be used to analyze
the car’s handling balance. Center temperatures are useful for directly
comparing the work done by each tire, while the Inner and Outer temperatures
are useful for analyzing the wheel alignment while on track. These values are
measured in three zones across the tread of the tire.
TREAD REMAINING
The amount of tread remaining on the tire once the car has returned from the
pits. Tire wear is very helpful in identifying any possible issues with
alignment, such as one side of the tire wearing excessively, and can be used
in conjunction with tire temperatures to analyze the car’s handling balance.
These values are measured in three zones across the tread of the tire.
Chassis
FRONT END
BALLAST FORWARD
To meet minimum weight requirements, tungsten blocks are installed within the
lower frame rails on the chassis. These blocks can be moved fore and aft in
the chassis, directly influencing the car’s Nose Weight value. The Ballast
Forward value is simply a measurement of the location of these tungsten blocks
relative to a reference point in the frame rail. Moving ballast forward in the
car raises Nose Weight, moving it rearward reduces Nose Weight.
NOSE WEIGHT
The vehicle’s Nose Weight is the percentage of total vehicle weight on the
front tires, directly adjustable through the Ballast Forward adjustment. Nose
Weight represents a rough approximation of the longitudinal Center of Gravity
location in the vehicle and has a direct influence on the high-speed stability
of the vehicle. Higher Nose Weight values result in a more directionallystable
vehicle, good for low-grip tracks and situations where the vehicle is set up
with extra front downforce. Conversely, lower Nose Weight values are good for
high-grip tracks and configurations with high rear downforce levels. Smaller
tracks will also see benefits from lower Nose Weight values, as it will allow
the rear of the vehicle to rotate easier
CROSS WEIGHT
Cross weight is the amount of weight on the car’s Left-Rear and Right-Front
tires relative to the entire weight of the car, displayed in percent. This is
adjusted via the corner Spring Perch Offset adjustments as well as Front ARB
preload and, to a very small extent, the Truck Arm Preload. For an oval car,
Cross Weight is one of the most influential settings for grip level while the
vehicle is in a turn. Higher Cross Weight values will add weight to the left-
rear and right-front, both stabilizing entry and helping drive-off on corner
exit. Lower Cross-Weight values will help the vehicle rotate and keep it
“free” in the corner to prevent speed from being lost, however too low can
result in unstable entry and exit. Due to this vehicle’s design with a Coil-
Bind front suspension, Cross Weight is a major consideration for front end
suspension configuration. See the section below for more information.
STEERING RATIO
The Steering Ratio is a numerical value for how fast the steering response is
in the vehicle’s steering box. This ratio can be thought of as the degrees of
steering input needed to produce one degree of turn on the steering box output
shaft. For example, a 12:1 steering ratio will require 12° of steering input
to rotate the steering output shaft 1°. A steering box with a lower ratio will
feel more responsive to steering inputs and will require less steering input
to reach the amount needed to navigate a corner. A steering box with a higher
ratio will feel less responsive and will require more steering input to reach
the amount needed to navigate a corner.
STEERING OFFSET
Degrees of steering wheel offset, achieved with a combination of installing
the steering wheel into the quick release mechanism off-center and adjusting
front tie-rods. This can be used to compensate for chassis settings which
place the wheel off center and is primarily a driver comfort adjustment.
FRONT BRAKE BIAS
Brake Bias is the percentage of braking force that is being sent to the front
brakes. Values above 50% result in more pressure being sent to the front,
while values less than 50% send more force to the rear. This should be tuned
for both driver preference and track conditions to get the optimum braking
performance for a given situation.
TAPE CONFIGURATION
Percentage of grill opening blocked off by tape. Increasing the percentage
reduces aerodynamic drag and increases downforce while shifting the downforce
balance forward, but reduces air flow to the cooling system and increases
engine heat. Decreasing percentage increases cooling but also increases drag
and reduces downforce.
FRONT ARB
DIAMETER
The Front Anti-Roll Bar (ARB, or Sway Bar) diameter affects the roll stiffness
of the front suspension. Increasing the diameter of the ARB will result in a
higher roll stiffness on the front suspension, helping to keep the chassis
flat relative to the racing surface, but can also increase understeer. While
not absolutely necessary, a large bar is typically desired (>2.00”) to
maintain bind in both front springs throughout the corner. For conventional
setups a smaller bar can be used.
ARM ASYMMETRY
The difference in length between the left and right sway bar arms can be
altered via the Arm Asymmetry settings. The “None” setting will set the two
arms at equal length, while increasing the setting will increase the
difference in length of the two arms. This can be used to produce multiple
effects, primarily serving to produce a higher anti-roll force on the right
front suspension than on the left-front, effectively rolling the chassis to
the left when under load. This can be used to correct excessive roll without
increasing the ARB diameter. A knock-on effect of asymmetry is a slight
increase in front end heave stiffness, or resistance to vertical travel. Since
the two different lengths of arms cause the bar to be twisted at different
rates, vertical travel will load the ARB, possibly leading to higher front
ride heights on straights.
LINK SLACK
The left-side sway bar linkage can be adjusted to either delay bar engagement
or apply a static load to the bar. The linkage itself is a slider-type
linkage, and any positive link slack will require the left-front wheel to
travel prior to the ARB experiencing any load. This adjustment directly
affects the bar’s Preload, outlined below.
PRELOAD
The ARB Preload is the static load in the bar while the vehicle is in the
garage. Preload adjustments can be used to alter the dynamic loads in the bar
while on track, and can be used to remove or add bar load in the corners and
on the straights.
ATTACH
A quick way to unhook the anti-roll bar to allow for static suspension
adjustments without bar twist confusing things; increase link slack and unhook
the ARB before making spring/ride height adjustments; attach and reduce link
slack (ARB preload) when done.
FRONT CORNERS
COIL BINDING
The front suspension for the NASCAR Trucks is designed to allow Coil-Binding
as well as Conventional-style setups. Coil-binding is when the coils in a
spring are all in contact with each other, thus creating a “solid” entity and
no longer allowing suspension travel. While this does create an extremely
stiff suspension, the aerodynamic benefits usually outweigh the drawbacks. For
the iRacing simulation, all of the front springs from 300lb/in to 450lb/in can
be bound within the suspension travel ranges allowed by the ride height rules.
Springs in this range are soft enough that they will bind simply from
aerodynamic loads and maintain the bind (or float just above it) for the
entire lap, so not much is needed to get it working. Tuning a coil-bind setup
can be broken down into two parts: Bind timing and Spring Length choice.
Timing when each front spring will bind is crucial, as it has a very large effect on the vehicle’s aerodynamic attitude, wheel loads, and overall balance. In most cases the left-front spring will bind first and stay bound until returning to the pits, with the right-front binding in the corners and releasing on the straights. To tune the timing, the primary adjustment is static crossweight. Increasing the crossweight will preload the right-front spring more and bind it earlier while allowing the left-front to drop slightly. Conversely, reducing static crossweight will preload the left-front spring, raising that corner but lowering the right-front. While it’s easy to fall into the trap of changing the ARB to counteract roll issues, this can cause one spring to stop binding, leading to long-run handling issues. Learning to use the crossweight to tune the car’s attitude is key in extracting the most performance out of this style of setup.
Sometimes crossweight will either move a corner too much or won’t move a corner enough, and in those situations you will need to change the spring length to compensate. While spring rate is used to manage loads on a Conventional-style setups, the spring rates for a Coil-Bind setup are used to change the length of the spring when fully bound. Higher rate springs will be shorter when bound while lower rate springs will be longer.
When setting up for a new track, it’s better to use the spring rates to set the rough heights and then use the crossweight to tune the roll attitude of the chassis. Most, if not all, of the roll attitude can be set through these two parameters, with a moderate- to large-diameter ARB being helpful for keeping the chassis consistently on each spring. It is not completely necessary, however, to use a large diameter sway bar for this type of setup to work.
CORNER WEIGHT
The weight underneath each tire under static conditions in the garage. Correct
weight arrangement around the car is crucial for optimizing a car for a given
track and conditions. Individual wheel weight adjustments and crossweight
adjustments are made via the Spring Perch Offset setting.
RIDE HEIGHT
Distance from ground to a reference point on the chassis. Front heights are
measured at the bottom of thechassis frame rail just behind the wheel well and
can be roughly identified via the skirt rivets at the bottom of the door.
Since these values are measured to a specific reference point on the car,
these values may not necessarily reflect the vehicle’s ground clearance, but
instead provide a reliable value for the height of the car off of the race
track at static values. Adjusting Ride Heights is key for optimum performance,
as they can directly influence the vehicle’s aerodynamic performance as well
as mechanical grip.
SHOCK DEFLECTION
Shock Deflection is how much the shock has compressed from its fully extended
length while under static conditions in the garage.
SPRING DEFLECTION
Spring Deflection is the amount the spring has compressed from its free length
while under static conditions in the garage. For the front springs on a coil-
bind setup, this is extremely important in that it shows how much travel is
available in the spring before binding.
SPRING PERCH OFFSET
Spring perch offset is used to adjust ride height and corner weight. Adjusting
this setting changes the preload on the spring under static conditions.
Decreasing the value increases preload on the spring, adding weight to its
corner and increasing the ride height at that corner. Increasing the value
does the opposite, reducing height and weight on a given corner. These should
be adjusted in pairs (left and right, for example) or with all four spring
preload adjustments in the car to prevent crossweight changes while adjusting
ride height.
SPRING RATE
Spring Rate changes how stiff the spring is, represented in force per unit of
displacement. On the front end of the vehicle, the spring’s behavior changes
based on the style of setup. For a conventional setup with spring values at or
above 500lb/in the springs will behave in a traditional fashion, managing
changing loads and maintaining chassis heights andaerodynamic attitude. On a
coil-bind setup with spring values below 500lb/in, the front spring rates
serve little purpose in influencing the handling balance and instead change
the length of the spring when bound.
BUMP STIFFNESS
Bump stiffness affects how resistant the shock is to compression (reduction in
length), usually in chassis movements as a result of driver input (steering,
braking, & throttle) and cornering forces. The front shocks play a significant
role in coil bind setups, with the Bump settings controlling how aggressively
the spring will bind. Higher Bump settings will result in a softer, less
abrupt bind, but can sometimes delay binding if set too high. Lower Bump
settings will bind the spring sooner, but the change in feel can be more
sudden.
REBOUND STIFFNESS
Rebound stiffness affects how resistant the shock is to extension (increase in
length), typically during body movement as a result of driver inputs. Higher
rebound values will slow extension of the shock, lower values will allow the
shock to extend faster. Higher rebound values can better control aerodynamic
attitude but can result in the wheel being unloaded when the suspension can’t
extend enough to maintain proper contact with the track. Excessive front
rebound can lead to unwanted oscillations due to the wheel bouncing off of the
track surface instead of staying in contact.
CAMBER
Camber is the vertical angle of the wheel relative to the center of the
chassis. Negative camber is when the top of the wheel is closer to the chassis
centerline than the bottom of the wheel, positive camber is when the top of
the tire is farther out than the bottom. Greater camber angles will increase
the cornering force generated by the tire, but will reduce the amount of
longitudinal grip the tire will have under braking. Excessive camber values
can produce very high cornering forces but will also significantly reduce tire
life, so it is important to find a balance between life and performance. For
ovals, set the left side positive and the right side negative. For road
courses, all four wheels should be set with negative camber.
CASTER
How much the steering axis is leaned back (positive) or forward (negative),
which influences dynamic load jacking effects as the car is steered. More
positive caster results in a heavier steering feel but decreases dynamic
crossweight while turning, as well as adding straight-line stability. Running
less caster on the left-front will cause the vehicle to pull to the left, a
desirable effect on ovals.
TOE-IN
Toe is the angle of the wheel, when viewed from above, relative to the
centerline of the chassis. Positive toe-in is when the front of the wheel is
closer to the centerline than the rear of the wheel, and negative toe-in (toe-
out) is when the front of the wheel is farther away from the centerline than
the rear of the wheel. On the front, toe-out is generally preferred. More toe-
out typically provides better turn in and straight line stability, but at the
cost of increased tire temperature and wear.
REAR CORNERS
CORNER WEIGHT
The weight underneath each tire under static conditions in the garage. Correct
weight arrangement around the car is crucial for optimizing a car for a given
track and conditions. Individual wheel weight adjustments and crossweight
adjustments are made via the Spring Perch Offset setting.
RIDE HEIGHT
Distance from ground to a reference point on the chassis. Since these values
are measured to a specific reference point on the car, these values may not
necessarily reflect the vehicle’s ground clearance, but instead provide a
reliable value for the height of the car off of the race track at static
values. Adjusting Ride Heights is key for optimum performance, as they can
directly influence the vehicle’s aerodynamic performance as well as mechanical
grip. Increasing rear ride height will increase rear downforce as well as
slightly increasing overall downforce and drag. Conversely, reducing rear ride
height will reduce rear downforce and reduce overall downforce and reduce
drag.
SHOCK DEFLECTION
Shock Deflection is how much the shock has compressed from its fully extended
length while under static conditions in the garage.
SPRING DEFLECTION
Spring Deflection is the amount the spring has compressed from its free length
while under static conditions in the garage.
SPRING PERCH OFFSET
Spring perch offset is used to adjust ride height and corner weight. Adjusting
this setting changes the preload on the spring under static conditions.
Decreasing the value increases preload on the spring, adding weight to its
corner and increasing the ride height at that corner. Increasing the value
does the opposite, reducing height and weight on a given corner. These should
be adjusted in pairs (left and right, for example) or with all four spring
preload adjustments in the car to prevent crossweight changes while adjusting
ride height.
SPRING RATE
Spring Rate changes how stiff the spring is, represented in force per unit of
displacement. Primarily responsible for maintaining ride height and
aerodynamic attitude under changing wheel loads, stiffer springs control the
chassis attitude better (less roll or pitch change) which is good for
aerodynamics and camber control, but mechanical grip is often better with
softer springs which allow for more track surface compliance but reduce
aerodynamic control. For ovals, a softer left-rear spring (relative to the
right-rear) is desired to prevent the dynamic cross from being too high in the
corners, which will result in a balance shift towards understeer through a
run.
BUMP STIFFNESS
Bump stiffness affects how resistant the shock is to compression (reduction in
length), usually in chassis movements as a result of driver input (steering,
braking, & throttle) and cornering forces. The front shocks play a significant
role in coil bind setups, with the Bump settings controlling how aggressively
the spring will bind. Higher Bump settings will result in a softer, less
abrupt bind, but can sometimes delay binding if set too high. Lower Bump
settings will bind the spring sooner, but the change in feel can be more
sudden.
REBOUND STIFFNESS
Rebound stiffness affects how resistant the shock is to extension (increase in
length), typically during body movement as a result of driver inputs. Higher
rebound values will slow extension of the shock, lower values will allow the
shock to extend faster. Higher rebound values can better control aerodynamic
attitude but can result in the wheel being unloaded when the suspension can’t
extend enough to maintain proper contact with the track. Excessive front
rebound can lead to unwanted oscillations due to the wheel bouncing off of the
track surface instead of staying in contact.
TOE-IN
Rear toe in this vehicle serves to introduce “Skew”, where the vehicle travels
through the air with a non-zero amount of yaw relative to the direction of
airflow, producing Sideforce. Setting the right-rear to a negative value and
the left rear to a positive value will add positive Skew, decreasing
crossweight and shifting aero balance forward slightly. Setting the right rear
to a positive value and left-rear to a negative value will add negative Skew,
reducing sideforce and centering the rear spoiler behind the greenhouse for
some toe settings. Positive skew is useful at large short tracks and
intermediate tracks, while negative skew will reduce drag for superspeedways
and aid in drive-off for smaller short tracks.
TRACK BAR HEIGHT
The rear axle is held in place laterally via a Track Bar, mounted to the left
side of the rear axle housing and to the chassis frame on the right side.
Overall height of the track bar dictates roll center location for the rear
suspension and thus affects roll stiffness, with a higher track bar increasing
rear roll stiffness and shifting the chassis balance to oversteer. Lower track
bar settings will increase lateral traction due to a reduction in roll
stiffness and roll center height. The track bar end heights can also be set to
different values, known as “rake” or “split”. A positive track bar rake, with
the right-side mounted higher, will increase oversteer on corner exit, as well
as adding skew through vertical travel. Negative track bar rake will increase
traction on corner exit, but will remove skew through vertical travel.
TRUCK ARM MOUNT
The rear axle is held in place longitudinally with two truck arms, mounted to
the bottom of the chassis underneath the driver compartment. The forward
mounts can be adjusted up and down, resulting in various anti-squat and rear-
steer configurations. Higher truck arm mounts will reduce rear end grip,
increase rear steer, add anti-squat, and reduce wheel hop under heavy braking.
Lower truck arm mounts will increase rear end bite, decrease rear steer,
reduce anti-squat, and increase the chances of wheel hop under heavy braking.
TRUCK ARM PRELOAD
Due to the truck arm mounting design on the rear axle, most chassis
adjustments will result in the truck arms applying a torque to the rear axle
housing. This preload has an extremely small effect on the chassis balance,
but can be removed to eliminate any potential issues. It is good practice to
reset this value to as close to zero as possible after making adjustments.
REAR
REAR END RATIO
The Rear End Gear Ratio is the ratio between the driveshaft pinion and the
differential ring gear. For all ovals with NASCARsanctioned events, this value
is either locked to one ratio or there is a choice of two ratios. Higher
number values produce better acceleration but reduce top speed, lower number
values reduce acceleration but result in a higher top speed.
ARB DIAMETER
The Rear Anti-Roll Bar (ARB, or Sway Bar) diameter affects the roll stiffness
of the rear suspension. Increasing the diameter of the ARB will result in a
higher roll stiffness on the rear suspension, increasing oversteer, while
reducing the ARB diameter will reduce roll stiffness and increase understeer.
A rear ARB is only available at Road Courses and has no effect on the chassis
on ovals.
PRELOAD
The ARB Preload is the static load in the bar while the vehicle is in the
garage. Since a rear ARB is only available at Road Course circuits, it is best
to keep this value as close to zero as possible when using a rear ARB to
prevent asymmetric handling issues. When the rear ARB is not in use, this
setting has no effect on the chassis.
ATTACH
A quick way to unhook the anti-roll bar to allow for static suspension
adjustments without bar twist confusing things; increase link slack and unhook
the ARB before making spring/ride height adjustments; attach and reduce link
slack (ARB preload) when done.
NASCAR CRAFTSMAN TRUCKS
Documents / Resources
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iRacing FORD F-150 Toyota Tundra Chevrolet
Silverado
[pdf] User Manual
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Chevrolet Silverado, Toyota Tundra Chevrolet Silverado, Tundra Chevrolet
Silverado, Chevrolet Silverado, Silverado
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