Measuring Stem's for handlebar clamp width

[Tommy27]

Posting this up for 2 reasons.

First it would be good to be know in general

Secondly I have two stems I'd like to sell and obviously would want to make sure they are accurately measured. Can someone explain to me exactly where I should be measuring

I've borrowed some digital calipers. The first a Fiamme Quill was easy enough. Seems to come out fairly consistently at 26mm. The 3T Mutant ahead though was much harder. I'm not sure if it's 25.4, 25.8 or 26??? Sadly no markings to make my life easier.

So if Someone can reply with a quick 'Dummies guide to stem handlebar clamp width measuring' it'd be much appreciated and hopefully not only will it stop me trying to put the wrong size of handlebar into any stems, but will also mean some people on here will soon be in possession of some great stems that were missing for their builds!

 

[mdvineng]

If there is still space in the clamp to close up, it will be 25.4mm.
Usual sizes here https://www.hilarystone.com/handlebars.html

 

[Tommy27]

where exactly should I be measuring the clamp diameter width between on the stem though? The Fiamme seemed pretty simple- I measured it in a few places and it seemed consistently to be 26mm , but the Mutant... that seemed to give off several widely varying readings.

It's this kind

(not my image)

When I've a chance I'll post pics up of both my actual stems.

 

[mdvineng]

The clamp should be measured fully closed. There needs to be a gap or it will not clamp tight enough!