So when I'm in the wheel object selection in the editor, it allows me to edit the front wheel but not the rear wheel.


It only says "Front" in this menu and doesn't allow me to change it so is this the only option, or is there a

way that I can edit the rear wheel as well?

There is a button "REAR identical - YES/NO". If it's set to YES, both front and rear wheels will have the same dimensions. If you set it to NO, a second set of buttons will appear below, allowing you to adjust the rear wheel dimensions separately.