I would say go only for the smaller 406 as there are a lot more tyre choices (almost all 20" folders have 406 wheels). I think there are like two choices for 451. I've noticed many of the mini velos from the east are now often with 451 wheels.
SJS are always good for a range of tyres. They have 5 options for 451 ERTRO-sized wheels.
SJS are always good for a range of tyres. They have 5 options for 451 ERTRO-sized wheels.