This is the most common carriage wheel in Accordion Shutters today.
It is sold in packs of 20, 40, 60 or 100.
Carriage Wheel Small Center Hole (Pack of 20)
22,00$Precio
The hole for this carriage wheel is 5/16" diameter. The outside width from wheel to wheel is 1 1/2" (see pictures). It's used in most accordion shutters currently.