Tire Size ?

i just picked up my dually and as far as i know it has the factory rims and tires on it wheel i went ahead and put it in storage so i cant go and look at it right away to see the size of tires that are on it but it has to bad tires on it that i need to change out so if any of you guys might know the tires size please let me know and if you might have 2 tires laying around thanks josh