- Extract the contents of the folder 'Tyres Machines' in the following directory:
C:\Users\(Your username)\AppData\Local\AcTools Content Manager\Presets\Tyres Generation

- Note that the contents should remain as .zip files in the 'Tyres Machines' folder, do not unpack the individual archives or they won't work.

- Now under content tab > cars in Content Manager, click replace tyres and instead of 'Find Fitting Tyres', instead select the tab at the top named 'Generate New Ones'

- Click on whichever tyre type you want to generate, some will be greyed out based on the default parameters of the vehicles original tyre size. Tyre machines with X or X-Treme in the name are not optimal, these have been modified to fit more sizes, only use these if the normal option is greyed out.

- Once the tyres are generated, drag them to the left, either overwriting existing tyres or creating a new set, remember to drag both the front and rears accross and in the correct positions.

- If you want to edit an original mods tyre size, you need to edit tyres.ini in the data folder under the headers CM_Original.