I have gone though the same issue dealing with rims.
One approach is to set categories for vehicle make, model and year. This for example will let the customer search for: Ford/Mustang/2004
Once you are in that category you can use product attributes to navigate though rim diameters, width, etc.
Another approach is to create a number of categories, Width, Load, Rim Diameter etc with child elements like-
And then assign each product to the corresponding categories: Width 205 + Rim Diam 16 for example.
Hope this helps a little bit…