Today I tried to fit a pair of tyres - same type and size- to a pair of factory prepped rims - same type and size. Rear first, tyre on, then a blast from the Joe Blow booster, and the tyre seats nicely and stays well inflated for several hours. Front, tried three times, no joy, just wouldn’t seat. CO2 blast did it, but deflated in minutes. Tried another tyre (same type & size) same result. Eventually replaced the factory tape, and bingo. What a pain.