Not ignoring the value of buying tires from a reputable dealer, just getting prices so I have some means of negotiation when I am prepared to buy some tires. It's been my experience that most dealers are willing to match prices if you can prove a valid vendor's price.
Rickson's website has the wheel width requirement for given tires on their website.
The rims I'm looking to get are 7.5" so I should be able to mount any tire between 245 and 285. The optimum size for these rims being 265/70R19.5.
Approved* Rim Widths
Tire Size Rim Alternate
225/70R19.5 6.0" 6.75"
245/70R19.5 6.75" 7.50"
265/70R19.5 7.50" 6.75"
285/70R19.5 7.50" N/A
*Approved rim widths are the industry standards
for tire wear and safety (and rear spacing on DRW
applications) set by the Rim & Tire Association.
When purchasing wheels for any application, the rim
width selected should always be dictated by which tire
size you plan to run in it now or in the future.
Rickson sells every tire I am considering. Their chart of a Rickson wheel size for a given tire size makes this pretty easy.