305's on an 11" rim
If it helps, I have run 325/50-15s on tens. Looks great but to wear evenly the pressure has to be down at less than 24psi. Which means I had to slow down for the turns. I compromised with 295/50-15s only because 305 -15s were recently discontinued and unavailable old stock, anywhere in Canada , back in the early 2000s.
I though about 17s but only for a couple of minutes.