I'm trying to buy a new stem for my old mountain bike. The stem on my current bike is stamped 25.4mm, a 1 inch stem, inside a 1 inch tube. I think I'm going to get a Profile Boa stem for the bike. But, they're listed as being a 25.4mm stem for a 1-1/8" steer tube, and 22.2 for a 1" tube. Shouldn't it be 25.4mm for a 1" tube? I'm confused. Anybody know which size I need?

A 22.2 stem is for a bike with a 1" headset/fork/headtube. The 25.4 is for the now common 1-1/8" headset/fork/headtube bikes.

Profile is correct.

a 25.4mm stem quill is for a 1 1/8" (outer diameter) fork. 22.2mm is for a 1" (outer diameter) fork.

Okay thanks guys. My mistake was measuring the inside of the steering tube, not the outside.

Sounds like it's the 25.4mm stem I need.

Thanks again.