Traction in GTA 3 & Vice City Handling
In the manuals for Gran Turismo, the tyres are described as the most important part of the car as they are the only point where it actually makes contact with the ground. This is also true in GTA and so one must be careful when choosing values for this setting. GTA has three settings which affect the traction between the tyres and the ground:
| Official Name | Description | |
|---|---|---|
| j | fTractionMultiplier
| Cornering grip of the vehicle as a multiplier of the tyre surface friction. |
| k | fTractionLoss
| Accelerating/braking grip of the vehicle as a multiplier of the tyre surface friction. |
| l | fTractionBias
| Ratio of front axle grip to rear axle grip; higher value shifts grip forwards. |
Traction Multiplier
R* use very high traction settings for their cars to increase the feeling of speed. However, experienced driving gamers prefer a more realistic setting so that they have to use braking, weight shifting and throttle control when taking corners. My basic guide to Traction Multiplier values is this:
| Value | Description |
|---|---|
0.50 | Old trucks |
0.55 | Normal trucks |
0.60 | Small vans and old cars |
0.70 | Old muscle cars and modern family cars |
0.75 | Executive sports cars |
0.80 | True sports cars |
0.85 | Exotic and high-performance cars |
0.95 | Production Touring racing cars |
1.00 | Grand Touring racing cars |
1.25 | Formula One racing cars |
Over 1.25 | Very special vehicles like dragsters |
These values can be set quite simply but try testing values up to 0.05 higher or lower just to make sure you get the best feel. This setting basically is the total cornering grip the car has and your car will often feel best with a strange value like 0.67, for example.
Traction Loss
This is quite a strange setting but it is basically the grip the vehicle has when under acceleration or braking. A value which is the same as the Traction Multiplier will result in a car with very neutral handling. If you reduce the Traction Loss setting, the wheels will spin more easily under acceleration and lock up more easily under braking. With very heavy vehicles like trucks you will normally need the Traction Loss to be higher than the Traction Multiplier to prevent wheelspin but it should not get over about 0.65 normally.
In general, the Traction Loss should be somewhere between 0.05 and 0.15 less than the Traction Multiplier. The 0.05 setting would apply to something very neutral like the Perenial whilst the 0.15 would apply to something like the Banshee. I normally try to keep the Traction Loss above 0.60 so that a reasonable braking force can still be used.
Traction Bias
GTA3 has a very sensitive response to Traction Bias when compared to GTA Vice City. For mid-engined vehicles, Traction Bias should be set towards the rear because they have wider rear tyres. In GTA 3, a setting of 0.49 should mean that the front wheels have around 49% of the available grip but it feels like much less. In fact, if you use a setting of 0.47 the vehicle will almost be impossible to turn. For big trucks which have four wheels at the back and only two at the front, a setting somewhere around 0.45 will simulate this.
In GTA Vice City the effect is more realistic, so a setting of 0.49 would suit the tyre difference on a powerful front-engine car like the Sabre. A setting around 0.47 suits exotic mid-engined cars like the Infernus. A setting of 0.33 truely represents the 33% grip that the front two wheels would get on a truck which has four wheels on the back.
For three-wheel vehicles, give them a Traction Bias as you would a three-axle truck. If the single wheel is at the back, then the setting would be about 0.53 in GTA 3 and about 0.66 in GTA Vice City.
Advanced Notes
The traction settings are not the only ones which change how the vehicle behaves when cornering. The CoM_Y setting alters the tendancy to understeer or oversteer and the CenterOffMass.Z changes how far over the vehicle will lean. A car which leans over further will lose grip more easily and so will a vehicle with a tendancy to oversteer or understeer. The Traction Loss will normally need to be changed when the CoM values change and it requires a lot of testing to get just right.
Make sure that your Braking Force and Braking Bias are set so that the vehicle does not quite lock up any of its wheels when braking on dry tarmac. By doing this ,dry weather driving can be as fast as possible and wet weather driving requires much more cautious technique becaue the wheels will stop turning when you brake.