Going from 205 to 215 mm tires should not be an issue for most folks. Even with a dual axle that is only decreasing the clearance between the two axles by 10mm. Since each tire has "two" sides (even though they are round) that is spread out around both opposite sides of tire. I have like six inches between tires so is no issue at all. The 15 inch rims are beckoning but I have already spent around $2000 in mods to this trailer since we bought a week ago so that may have to wait another summer or set of tires.
Official caretakers of Sasha & Blakely the King Charles Cavalier Spaniels. (We drive their camper around for them)
2014 Coachman Catalina 25 RKS Deluxe, Anderson WDH, 2016 Ram 1500 Laramie 4x4 for TV