I have a 90 Dodge B250 camper van conversion. I am finding that 235/75 -15 tires are becoming hard to get. Has anyone done any upgrading to larger diameter wheels such as 16" in order to switch to a more popular tire size. I would like something that is able to retrofit without changing hubs/axles or using adapters. I would appreciate information from anyone with experience on this. Thanks in advance.........Vic.