ok a 245-50-16 tire...
a 235-60-16 tire
how does that work i always get confused.. the higher both numbers the bigger the tire?

 

The first number is the width in mm of tire (or tyre, as they say across the pond ) The middle number is the % of hight vs. width. So the 60 series tire is 60% as tall as it is wide. So if you have a 245/50 tire it is the same width as a 245/40 tire, but taller. This way, you can have a 245/50/16 and it will be 25.7" diameterand a 235/60/15 tire is 27.1" diameter. Even though the rim is smaller, the tire is a higher percentage of width, so it will be larger around.

I am running 295/30/18"sand are 25.1" diameter. Myyear and makecame stock with 245/45/17"s on 8" rims and tires are 25.7" diameter. My rearwheels are a full 2 1/2" wider and are slightly over 1/2" smaller diameter due to 30 series tires

Jazzer