Why would I want to customise car classes?

The main reason for caring about car classes in Crew Chief is to have a good Crew Chief experience for vehicle classes in mods that Crew Chief does not support out of the box. Crew Chief uses the Class definition for information about wheel sizes, brake types etc. There's a lot of awesome 3rd party content, but not all use the class names and the Crew Chief team can't cover them all. That's where this mechanism becomes helpful.

Single-class vs Multi-class event

Crew Chief uses Car Class to distinguish between multi-class and single-class races. If race is a multi-class race, Crew Chief will compare your lap times with lap times of vehicles of the same class. The problem is that sometimes mods are authored in a way that the car class name is different for vehicles in the same class. For example, there might be "A GT3" class name for vehicle of brand A, and "B GT3" for vehicle of brand B. If you would like Crew Chief to treat both as the same class you will need to map "A GT3" and "B GT3" class names to Crew Chief GT3 class. That way, such a race becomes a single class race.

What can be customised using this mechanism?

More detail in this forum post Customising Car Classes

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