Not too long ago, I had my own question as to how large a tire I could put on my STOCK rims... and I needed to know the WIDTH of the rim in order to figure that out. I got help, on these forums, in resolving that question. I have noticed that this sort of issue (wheels rims tires what fits?) comes-up rather frequently. I'm not one to do "lifts" and put over-sized rims and tires on my truck, but I see a lot of it being done, on my local streets and highways. Out of curiosity, I wondered if there were any online resources--CHARTS / CALCULATORS--actually, where anyone could readily find their own answers. I found the following site: http://www.rimsntires.com/rt_specs.jsp -- "Play" with specs, try different settings, compare results, see difference... Find what fits" I'm wondering if any of you find it to be worth using / bookmarking?