Okay, I dunno.
The stock Kenda I took off was 225/50R15
I ordered, received and ruined a BF Goodrich 225/50R15
A tire store sold me a Khumo 225/50R15
I measured it and it was identical to the Kenda.
The Kenda & Khumo seem to me to be exactly the same size.
This website that explains tire sizes seems to say that if the numbers are the same, then the physical dimensions have to be the same as they offer a calculator that displays the diameter & circumference of the tire based on the size.
http://www.car-videos.net/info/tirespecs.asp
So as senile as I probably am I think that, within reason, the physical tire size of height and width is the same between two tires of the same size regardless of manufacturer.
The end.