# [ODE] Simulating Wheels

borje iqt-net at home.se
Wed Nov 5 18:31:30 MST 2003

```Hi,
I have been modifying a racesim (F1C) for some time and they have a pretty
good tire modell into their physics engine that can be tweaked to simulate
diffrent types of tires.
This is what a tire file looks like.
LatCurve, BrakingCurve, TractiveCurve uses a slipcurve or you can define
diffrent slipcurves for diffrent things. I have with succes been able to use
pacejka curves for LatCurve, BrakingCurve, TractiveCurve.
Ive been looking into building my own racesim for sometime but have always
seen it difficult to build a proper tire modell, but since i found ODE and
now this thread i am very very much loking forward to this progress although
i havent used ODE that much yet.

[COMPOUND]
Name="Hard Compound"
Front:
DryLatLong=(1.6085, 1.9839)           // Lateral/longitudinal coefficients
in dry weather
WetLatLong=(0.8612, 1.0621)           // Lateral/longitudinal coefficients
in wet weather
RadiusRPM=4.65e-6                     // Increased radius per unit RPM
Width=0.355                           // Width of tire
SpringBase=54500.0                    // Base spring rate with no pressure
SpringkPa=1331.0                      // Spring rate per unit pressure
Damper=676.0                          // Damping rate of tire
LoadSens=(-7.60e-6, 0.405, 15200.0)   // Load sensitivity of tire (initial
slope, final grip multiplier, final load)
LatPeak=(0.099, 0.373, 19550.0)       // Slip range where lateral peak force
occurs depending on load
LongPeak=(0.099, 0.373, 19550.0)      // Slip range where longitudinal peak
force occurs depending on load
LatCurve="Default"                    // Slip angle curve (data uses
normalized angle)
BrakingCurve="Default"                // Slip ratio curve under braking
TractiveCurve="Default"               // Slip ratio curve under acceleration
Camber=(3.17, 0.107)                  // Peak camber angle and additional
lateral force gained
RollingResistance=1435.0              // Resistance torque (Nm) per unit
deflection (m) on ground
Heating=(4.87e-1, 1.07e-2)            // Heat caused by (rolling, friction)
Transfer=(6.12e-3, 3.86e-3, 1.14e-4)  // Heat transfer to (road, static air,
moving air)
WearRate=9.303e-008                   // Wear rate constant
Softness=0.50                         // Softness is now just for AI use
AISens=(0.405,15200.0)                // Simplified AI load sensitivity
(final grip mult, final load)
AIGripMult=1.090                      // Grip multiplier for AI vehicles
(due to tire model simplification)
AIPeakSlip=0.085                      // Simple peak slip angle for AI
vehicles
AIWear=1.334e-008                     // AI wear rate constant
OptimumTemp=114.0                     // Optimum operating temperature for
peak forces (Celsius)
OptimumPressureBase=115.0             // Base pressure to remain flat on
ground at zero load
OptimumPressureMult=0.0066            // Multiplier by load to stay flat on
ground
Rear:
(Here comes same stuff again for rear tires)

```