hi, i have a 182 with cup packs, and the tyres on them are 205.45.16, but my friends data base says it should have 195, and my new turinis are 195 and friends 172 are 195 and my cup wheels and 172 cup wheels are both 7,5. what is the correct size. as my 182 tyres look ok, but cups look alil streched, but everyone says there correct?