True tire sizes

Hey guy I need some advice. My dad has a bruin with 25x10x12 mud lights on the back. I got a tape measure out, and at 7 psi, they only measure 23 inches tall. What gives? I’m about to go pic up a 2007 350 grizzly irs that needs tires. I was gonna order 26 inchers, but if I find a tire that’s a true 25.inch, and doesn’t just say it on the side, then I think a 25 inch tire might be ok. Any advice?

True tire sizes

Hey guy I need some advice. My dad has a bruin with 25x10x12 mud lights on the back. I got a tape measure out, and at 7 psi, they only measure 23 inches tall. What gives? I’m about to go pic up a 2007 350 grizzly irs that needs tires. I was gonna order 26 inchers, but if I find a tire that’s a true 25.inch, and doesn’t just say it on the side, then I think a 25 inch tire might be ok. Any advice?