I believe those are 5" wheels. Weber kettles take either 6" or 8".
The other critical dimension is the hub diameter. Weber triangles are 3/8. Most replacement wheels are 1/2" I have used steel wheels from Tractor Supply Co on a couple of my Webers, but have had to use a bushing to make the 1/2" hub work.
Winz
PS - congrats MINIgrillin on becoming a WKC "Ranger" Looks like I just made it over the line as well!