[dsraven]

i use those sites quite a bit when tire sizing. playing with different options across a number of open tabs on google. tire size, wheel size etc. trying to keep the tire contact patch where it needs to be for the steering geometry can help the handling of the vehicle. look up scrub radius on any racing enthusiast site and it could take you a week to go through it all, lol.
in the end, the contact patch centerline of the tire on the road works with the steering axis inclination built into the spindle (a line drawn through the upper and lower ball joints) to affect how the vehicle handles and how it may or may not try to follow every crack in the road etc. it also works with the other steering angles as they all affect each other. worth some time reading up on that stuff so you get the front end the way it needs to be.