By 22", do you mean 451 bead seat diameter, or a different one?

20" is typically 406mm, so that's almost 2" difference, but 451 is also typically called 20". Also, 451 tires tend to be skinner and high pressure, as 451 is typically used for fast road riding, so the actual outside diameter is closer to 406-44 than the difference in bead seat diameter would indicate.