hello,

Go a real newbie style question... please be gentle.

I have a thirty year old road model, that I'm trying to tame.
I have some spare road bars that I want to replace the riser bars,
that were put on it by the last owner.

I want to use a threadless stem, so it's easier to swap out handlebars.

My question is : What stem do I need ? ( the two sizes in bike speak, what is the Bar Clamp Diameter and the tube size ? )

The Clamp Diameter at the moment on the riser is : circumference is roughly = 7cm 2.8 inches.
The handlebars, taper from 8.3cm/3.25 inches in the center to 7.3cm/2.9 inches on either side and down into the drops. Do I have a 1" or 1 1/8" fork ?

Many thanks in advance,
Psy.