gauge measurements?

[jaden]

hey, I'm just wondering... how are gauges measured? is it by the size of the face or by the size of the whole thing? they sell them in 2 1/16th and 2 5/8ths the gauge i have is 2 1/16 face and 2 5/8ths whole diameter... which size gauge should i but to match the size?

 

[Defiant]

The gauge size is the diameter of the hole it will mount in. The bezel usually adds another ¼" or so to the outside diameter, and takes away about half that of how much face you can see.