I am just curious if anyone has come across a site/store that has p185/40/r15? I searched Ebay and could find 185/50/15, but I would like a lower profile .

and what car do you propose using that size on ??? with the tire being under 21" in diameter and having a load capacity slightly higher than a large dog I don't see it working on anything listed in your signature ... that and the fact nobody makes that size

Okay, I understand, but was curious as to what is the lowest profile height for the 185mm width. I am assuming it is 50%.

Would you happen to know about what impact different tire/rim diameters have on the speedometer reading?