wheels of different sizes

my model wheels of different sizes , how to change the standart script(CarSetup.py, PowerTrain.py) so that the wheels rotate correctly relative to each other?

You need to set the right radius -> search for radius.

As monster said, in one of the scripts you will find variables for each wheel, just change those radii to the sizes you need.

radius changed ,

but the machine is not stable , she flips
prompt,how to make it more balanced?

Where are the center of your objects? Are they in the right places?

Yes,the problem was at the center of gravity of the object