How are bike stems measured?

[Jim R]

I recently bought a Trek 2100 and I need a shorter bike stem. I am sure that I can buy one cheap on ebay but I need to figure out what size I actually have and what size I need. How they are measured?

The one on the bike is about 4.5" (or about 115mm) from the center of the post to the center of the handlebars. It actually separates the post from the handlebar by about 3" (or about 75mm). Would anyone have any idea what size this would be or how they are actually measure? Thanks alot.

 

[boudreaux]

I recently bought a Trek 2100 and I need a shorter bike stem. I am sure that I can buy one cheap on ebay but I need to figure out what size I actually have and what size I need. How they are measured?

The one on the bike is about 4.5" (or about 115mm) from the center of the post to the center of the handlebars. It actually separates the post from the handlebar by about 3" (or about 75mm). Would anyone have any idea what size this would be or how they are actually measure? Thanks alot.

depends....For all thredless and welded quill(threaded) types, it's c-c from the center of the steerer clamp or quill to the center of the bar clamp along the SIDE of the extension... With older cast or forged aluminum types, it's c-c from the stem bolt to the center of the bar clamp along the TOP of the extension, but with some exceptions...Don't expect all ebay sellers to know this.

 

[Mansmind]

depends....For all thredless and welded quill(threaded) types, it's c-c from the center of the steerer clamp or quill to the center of the bar clamp along the SIDE of the extension... With older cast or forged aluminum types, it's c-c from the stem bolt to the center of the bar clamp along the TOP of the extension, but with some exceptions...Don't expect all ebay sellers to know this.

LOL..seems we've been here before.