Originally Posted by The Fixer
I didn't realize tubing thicknesses were different between the two...
Steel steering tubes, in general, have 1.6mm thick walls.
So a 1" (25.4mm) steerer minus 3.2mm of walls turns into the famous 22.2mm I.D.
And an 1 1/8" (28.6mm) steerer has a 25.4mm I.D.
Our threadless 1 1/8 forks have thinner walls in the portion of the steerer that is inside the head, at least on longer frames. This saves a little weight.