Tire substitution chart: Where?

[brians356]

Hello,

I recently stumbled on a link to a tire substitution chart, but didn't bookmark it. It was unique in that you entered your current tire size at the top, then it showed a whole page full of tire sizes, showing the differences in specs for each from the current tire. In particular two columns: 50 mph (current) = XX mph (sub), and 1000 miles (current) = xxx miles (sub).

Anyone know that link?

Brian