Ok. In that case I think you’re right. The BBP 7.25 and 8.25” are the same width, so, Fawkes experience is right on. I had a simile experience with a BBP 7.25”, I barely fit a set of 17x9’s with 275/40/17’s with a 4.75” backspace. Don’t let the number fool you though, on a 17x9 there’s very little tire overhanging the rim, on a 15x8 with a 275 they’re be a lot and in my case the section width was 10.8”. And I still would have probably needed another 1/8” of spacer to drive it without rubbing.
With an 8.25” you’d want a 15x8” with a 4” backspace to clear 275’s without spacers.
