Actually Kumho makes a H rated tire in 275/60/15
http://www.tirerack.com/tires/Spec.j...odel=Ecsta+STX
Why no 235/60/15 or 245/60/15"
This looks like a tire design for the 18, 19, 20, 22, 23 & 24" sizes. I am not a rocket scientest but if there is a market for 24" tires it is probably not any larger than the market for good 15" street performance tires.