I just bought a Tacoma and the Wheel and Tires are now size 235/75/15. I would like to change the tires to size 31x10.5R15. I looked at the label on the Driver Side Door and it says 10.50R15. What does the 10.50R15 mean? Is it the recommendation size? Since the Wheel is 15, can I change the tires to size 31x10.50R15? I need your help please.