simple question. what is the max tire size i can get with a 15x8?

 

245

 

To avoid major "rubage", 205/55-15 or 225/50-15. That's if you want to keep the speedometer accurate & avoid destroying the wheels at the same time. Outside of that, you won't find anything wider that will keep the speedometer accurate. A 245/45-15 tire would be ideal, but that size doesn't exist & if it does, it will most likely be some super fat r-compound.