I’m guessing your coach is overloaded at the rear. The yellow sticker recommendation (65?) typically is what the tire manufacturer would recommend for your vehicle at it’s maximum allowable weight (GVWR). You absolutely should get weighed, look up the specs for your tire model for that weight and go with that. It won’t be 80 unless you are at the tires upper load limit. Beyond that, I wouldn’t worry about the tire spacing.
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