Guys, here is a link to an online tire size calculator.
Putting the wrong size tire on your rim may look ok but it can really screw up your brakes and speedo.

It's simple to use.....just enter the stock tire size in the upper box and then enter the sizes you are planning to go with (in the section below) to see if your planned size is safe or also if your speedo will be off.

It's a great tool that could save you some grief down the road.

Tire Size Calculator - tire & wheel plus sizing