Originally Posted by
Leisesturm
I don't know of any drop-bars and flat bars that fit the same stems. I don't know of any drop-bar brake levers and flat-bar brake levers that fit the same bars. These conversions are done all the time but some are understating the degree of difficulty. In many cases the stem length that was fine with the drop bar needs to be increased by as much as 20mm or more when going to flat-bar.
I checked my 3 handlebars from Japanese 80s bikes Nishikis and Bridgestone. They are all 25.4mm - the standard size for most flat bars. It's also easy to add shims to 26.0mm stems, even made from tin cans.
Many old mixtes have too aggressive geometries, so going with the same stems and swept-back handle bars will allow to lean less and sit more comfortably.
Sakae Road Champion 25.4mm drop handle bar.
These Dia Compe brake levers fit any handle bar with any diameters. 2mm more or 2mm less, it doesn't matter.
