Originally Posted by FBinNY

There are nominal sizes, which is what we call things, and there the actual sizes which are close but not always spot on, since nothing is truly perfect. 3/1000ths of an inch is a tiny amount and within the manufacturing tolerance for this kind of stuff. Ot possibly you pressed a bit hard with the caliper and got a low reading.

Don't be confused. For practical purposes 1.122 = 1.125, and you need a 1-1/8" fork. If you buy a 1" fork you'll be off by 122/1000ths of an inch which is in a totally ballpark.

Look at it this way. If you wear size 10m shoes, which would you buy, a slightly oversize size 10, or a size 9?