Try this tool: Tire size calculator Then check against TireRack specifications. You'll see that overall diameter and sidewall height will vary, even amongst similarly sized tires. Also pay attention to tire weight. Most of the LRR tires will be close in weight but you will see other tires the same size that weigh significantly more. I have not searched tires small than the stock size, but I can tell you that the 195/55/16 size does not have a lot of choices. I've seen several posts where people have chosen to move to 205/55/16 as there are way more tires to choose from.
