So i have a complete model of a wheel i want to use in game i just have no clue how to make it usable in game any help is appreciated.
Copy one of the in game wheels of the similar size and then just change the name of it, and change the model that it uses. As long as it is the same size as the in game rims it should work fine.
There isn't one ingame... You should read on wiki a bit about jbeam and try resizing the laready present wheel, like one of the SBR4 wheels (i think it has 20s). Then if you get it working with just the resized sbr4 rim, try resizing the tires. After you done that, change out the model for the one you've made.