allright people, I guess I misunderstood how tires are measured. I ASSUMED that the profile (second number) was X% of the width (first number). therefore, 215/45, the stock tire, would have a width of 215mm and a height (from the rim) of 96.75mm (45 percent of 215). I haven't actally measured my tire- maybe I should have. UNDER the following assumption, I found a tire with what I thought was approximately the same profile- 245mm width and 98mm height (40 percent of 245).

I don't know much about tires. one site that I read on the internet said that this is more or less how you read the numbers, and a friend told me that in this case, the tire would simply have less of a curve between the contact patch and the sidewall.

I checked and found a wiki article here that explains it the way I thought it was. what am I missing?