Traction is a number (related to G force) that indicates the ability of the vehicle to hold the road while cornering. The number depends upon the road surface, the weather, the contact patch size, the tire compound and pressure, the suspension system, and other factors. It is not related to turn radius, speed, power, vehicle weight or center of gravity. Use this guide:
Street cars 0.6 to 0.9
Modified street cars 0.7 to 1.0
Race cars 0.8 to 1.0
Aero race cars 1.0 up... (try 1.0 + (downforce / weight))
Multiply this number by a road surface factor:
Concrete 1.1
Asphalt 1.0
Wet 0.5 to 0.7
Dirt, sand 0.3 to 0.6
Ice 0.05 to 0.1
Adjust the result depending on your chassis and conditions.