Originally Posted by Viich

So - picking up on Duragrouch - The 451 size has been picked back up in racing as the "OS20" size, some people refer to it as "cheater size" as the wheel is bigger than the 20" classes allowed until this new name happened. There are a few good race tires and rims out there for it for sure. It's going to raise your bottom bracket and mess around with your geometry a little.

Originally Posted by Duragrouch

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 than the difference in bead seat diameter would indicate.