Hello, Hoping someone can help me (because I can't find anything relating to this). I've edited a TGM to fit a size I want, but I'm struggling to see or understand how you edit the rim width and size. Is it not possible to edit that? I've got 180-550-R13x6 but I'd like 180-550-R13x8. So, how do I make the 6 inch into 8? Ta muchly!