Where did our race number sizes come from

[skidlids]

As the title says
Where did our race number sizes come from

ACU hand book says minimum of 140mm high both front and sides yet DD rules say 160mm high front and 120mm high for the sides,
not a worry for me as my numbers are a bit on the large size.

[Rattler]

Gotta think that the ACU rules would supercede, but if you've got the option, go for the larger I reckon.

Tim

[phoenix n max]

I followed the acu rules.