Wheels and additional Handling

Edit
Date: January 9, 2017
Authors: Gel38
Categories: Parameters
Tags: car_making

;====================
; Car Wheel details
;====================

WHEEL 0 { ; Start Wheel
ModelNum 1
Offset1 -24.000000 -1.000000 37.000000
Offset2 -4.500000 0.000000 0.000000
IsPresent TRUE
IsPowered TRUE
IsTurnable TRUE
SteerRatio -0.500000
EngineRatio 12000.000000
Radius 12.000000
Mass 0.150000
Gravity 2200.000000
MaxPos 12.000000
SkidWidth 10.000000
ToeIn 0.000000
AxleFriction 0.020000
Grip 0.014000
StaticFriction 1.500000
KineticFriction 1.500000
} ; End Wheel

WHEEL 1 { ; Start Wheel
ModelNum 2
Offset1 24.000000 -1.000000 37.000000
Offset2 4.500000 0.000000 0.000000
IsPresent TRUE
IsPowered TRUE
IsTurnable TRUE
SteerRatio -0.500000
EngineRatio 12000.000000
Radius 12.000000
Mass 0.150000
Gravity 2200.000000
MaxPos 12.000000
SkidWidth 10.000000
ToeIn 0.000000
AxleFriction 0.020000
Grip 0.014000
StaticFriction 1.500000
KineticFriction 1.500000
} ; End Wheel

WHEEL 2 { ; Start Wheel
ModelNum 3
Offset1 -24.000000 1.000000 -36.000000
Offset2 -6.000000 0.000000 0.000000
IsPresent TRUE
IsPowered TRUE
IsTurnable FALSE
SteerRatio 0.100000
EngineRatio 12000.000000
Radius 13.000000
Mass 0.150000
Gravity 2200.000000
MaxPos 12.000000
SkidWidth 10.000000
ToeIn 0.000000
AxleFriction 0.050000
Grip 0.014000
StaticFriction 1.500000
KineticFriction 1.500000
} ; End Wheel

WHEEL 3 { ; Start Wheel
ModelNum 4
Offset1 24.000000 1.000000 -36.000000
Offset2 6.000000 0.000000 0.000000
IsPresent TRUE
IsPowered TRUE
IsTurnable FALSE
SteerRatio 0.100000
EngineRatio 12000.000000
Radius 13.000000
Mass 0.150000
Gravity 2200.000000
MaxPos 12.000000
SkidWidth 10.000000
ToeIn 0.000000
AxleFriction 0.050000
Grip 0.014000
StaticFriction 1.500000
KineticFriction 1.500000
} ; End Wheel

This corresponds with the "Model Filenames" section. This setting uses the numbers -1 to 18 and determines which model is used. If no models are used, this number should be set to -1, otherwise from 0 to 18. In this case you want the number corresponding with one of the tire prm's.

This is the same as the offset setting for the body of the car. Offset1 is the placement of the visual model of the wheels, based on an XYZ coordinate system.

X-0, Z-0, Y-0

X = width of car (This is the 1st number) Y = length of car (The 3rd number) Z = height of car(2nd number)

Positive numbers on the X axis place the model to the Right, whereas, Negative numbers place it to the Left.

Positive numbers on the Z axis will move the model down toward the ground, whereas, Negative numbers will bring it up. This also affects the ride-height of the car. Positive numbers will cause the car body to move upwards, while the wheel remains on the ground. Negative numbers will lower the car body, however, the wheels will not lift off of the ground until the car body has touched the ground.

Positive numbers on the Y axis move the model forward, whereas, Negative numbers it to the rear

This setting is just like Offset1, but instead of placing the visual model of your tires, Offset2 places the physical tires. These tires are invisible, thus, you have to look at tire skid-marks to see where they're being placed. Offset2's point of origin is set by Offset1, and can be modified from that point.

This setting can have impact on the handling of your car. Such as, a wider wheel base will increase stability during cornering (unless too wide). Making the car wheelbase longer can cause the car to react sluggishly and increase the turning radius.

This is a TRUE/FALSE flag to say if the wheel is visible or not.

This is a TRUE/FALSE flag to say if the wheel has power flowing to it from the engine or not.

This is a TRUE/FALSE flag to say if the wheel has steering or not.

SteerRatio tells Re-Volt firstly how much your steering wheels will turn. A number of -6.25 will turn the wheels a complete 360 degrees. It also covers the speed of your steering. The more angle you have, the faster the car will steer. In turn, this affects the stability of the car, making it stable or twitchy.

SteerRatio uses negative (-) numbers for the front wheels, and positive (+) numbers for the rear wheels. Most generally, for the front wheels, a number of about -0.25 is good for R/C cars (and sometimes simulation handling). However, if you wish slightly smoother steering lines, or more understeer, you can bring the number a little closer to 0. If you wish for simulation style handling, -.15 seems to be good. However, dropping below (or rather, above) is not recommended, as you will not be able to properly navigate the turns.

This is the power which is delivered to your tires. Increasing this number will increase the power, of the tire. The front-right tire should have the same power as the front-left tire. Rear tires may have a different EngineRatio than the front tires.

Increasing the power can also affect your acceleration, making it much faster. It can also have an impact on your handling, such as, increasing understeer. Lowering the setting can encourage better, more stable cornering. This setting also affects tire squeal (wheel spin).

Think of this setting as your torque distribution. This can be used as a way to evenly distribute the power of the wheels of a 4WD car. If you wish to have a distribution of 40/60 torque split, keep a number in mind (say 30,000) and then multiply by .6 (or.4). Whatever the amount comes from the equation, that amount of power goes to the front or back wheels.

Example equation:

In this case we want a 25/75, torque split ratio, with a grand total of 30,000 Engine Ratio Units.

Rear Tires

30,000 x 0.75 = Rear Engine Ratio (For each rear tire)

Front Tires

30,000 x 0.25 = Front Engine Ratio

This is the physical (not visual) size of the tire in RV Units. If this setting is not set with the size of the 3d model of the wheel, the tires will either float in the air (if the number is too big), or sink into the ground (number is too small).

Adjusting this setting also affects the acceleration of the car. Smaller tires require less EngineRatio to turn the wheels more quickly, and likewise, larger wheels require more EngineRatio to correctly power them. Tires which are overpowered will produce wheel spin and will not grip to the ground as well.

This is the weight of the tires in kilograms (kg). Increasing this setting for the tires will increase the overall grip of the tires, making it slightly easier to climb snowy/icy hills, and also less likely to roll. If the tire is too heavy (I.E.: Over 1 kg), when in the air, the tires will move up through the car body, then upon landing will do funny things. This, possibly could be corrected, as this setting corresponds to the MaxPos setting later in the wheels section.

Increasing the mass of your tires can have a very tiny effect on your acceleration and top speed. (For this to happen, the weight needs to be 4 kg or more). If you wish your tires to be so heavy, you may have to slightly increase the EngineRatio setting to accomodate. A setting of more than 6 kg is not reccommended as it will cause the wheels to fly about during impact (however, this may be correctable by the afore mentioned settings).

This setting tells Re-Volt how long it should take the tires to catch grip after a jump. A setting of 100 will cause the tires to catch grip after about 5 seconds. Having a lower setting can also affect how the car goes onto inclined planes.

Gravity also affects the ride-height of the car/wheels. The norm for this settng is 2200. A setting of about 20,000 will lower the car nicely, but 200,000 will put the car through the floor. Very high numbers will affect the top speed of the car.

This is the vertical movement of the tire on it's respective "spring", in terms of RV Units (vertical travel) divided by 2

Equation:

U = RV Units M = MaxPos

U / 2 = M

MaxPos, will also affect your handling. A setting of 6 to 8 seems to be fine for most R/C style cars, however, a setting of 1 will cause an extreme amount of understeer. Increasing this number in excess of 50 - 100 seems to encourage a heavier, more simulation feel of the car. Doing this will give the car slightly smoother steering lines. Any numbers above 100 do not have much effect. However, placing the number in excess of 50 can cause the tires to come through the top of the car.

This is the width of the wheels skid-marks in RV Units. The placement of the skids are set by "Offset2". This setting should match the width of the wheel model. Making the Skidwidth excessively wide (or thin) seems to have no effect on top speed or handling.

ToeIn is usually the angle that the tires are pointed toward (or away) from the center of the car. This (depending on if the car has Toe-in or Toe-out) can increase (or decrease) understeer/oversteer in a car. However, in Re-Volt this setting seems to be irrelavent, having no function, as, any input value is forced back to 0.

This is the value for the amount of friction produced by that wheel on the axle. Increasing this number increases the amount of friction on the axle. This in-turn decreases braking distance and the distance to stop when the gas is let go. However, despite the fact that friction is increased on the axle, this will increase the speed of the car. It may also make the car more twitchy when the number is set too high.

Lower numbers will decrease the friction on the axle. This will increase braking distance needed to come to a full stop, and also increase the distance to stop when the gas is let go. Despite the fact that the friction has been lowered, decreasing the AxleFriction number will decrease the overall top speed of the car.

It is not recommended to go over a setting of 0.3.

This is the general grip of the individual wheel. Higher values will cause it to stick to the track better, like a magnet. Lower values will decrease this friction.

This setting can be used to stablilize RWD cars by increasing the grip on the rear tires by a value of 0.006 over the front tire grip. This will produce a handling result of the Ferrarri 458 Italia on Forza Motorsport 4. A setting of 0.025 will give much stability to the car. Anything above 0.025 is not recommended, as it will increase tire squeal, and numbers in excess of 0.03 will decrease the top speed of the car.

Increasing the Grip setting on the front tires can lead to oversteer. Increasing front grip too much can cause a near 0 point turn radius. Therefore, it is not good to increase front grip unless you wish to have a car which snaps into the turns, however, steering corrections become near impossible. A perfect example of this would be to think of a Smart Fortwo that is fully tuned and RWD.

This is the wheel's resistance to movement while not moving (if hit or on an inclined plane). It also affects the amount of grip the tire gets when the gas is depressed.

Higher values increase the friction produced, whereas lower values decrease friction. This setting should be higher than KineticFriction. It is not good to bring this setting close to 0.

Lower values (in tandem with the KineticFriction setting) can be used to make the car drift through the corners with ease. Depending on how low the friction is, the picture can be like butter sliding on a hot plate.

This setting can have an adverse effect on handling.

This is the wheel's resistance to movement while moving. It also affects the amount of sliding that occurs when the brakes are hit.

Higher values increase the friction produced, whereas lower values decrease friction. This setting should be lower than StaticFriction. It is not good to bring this setting close to 0.

Lower values (in tandem with the StaticFriction setting) can be used to make the car drift through the corners with ease. Depending on how low the friction is, the picture can be like icecream sliding on a hot plate.