Sure it does. Disable it. Then get into the game and buy a tire. While buying it, increase rim diameter to something like... '17' and then try maxing out tire width and height. Make the purchase. Now save and exit to main menu, then enabled Unreal sizes. Go back in and purchase that same tire... rim size 17 and max out tire width and height again. You should see a noticeable difference in how wide and tall the tire can be compared to your first purchase. This difference maybe even more noticeable with smaller and larger rim sizes--where you can go smaller / larger for rim diameter and more extreme tire dimensions--both smaller and larger.

Thank you, My problem is modders are making mods with 11 inch wheels. In the game you can only go down to 12 inch wheels and tires.

Yeah, that could present an issue then. Would have to replace the rims with the 12" one's I guess.