I have heard that there is a tire size chart that calculates tire size (width) by the weight of the rider and gear. I cannot seem to locate this chart. I have two pair of tires, one is size 700 X 32 and one is size 700 X 37. Both are Continental Top Touring 2000. I am 195# and my gear is 40# using front and rear panniers. My riding will be on paved roads. If you know of such a chart would you mind sharing.