Hello there folks. I have tried to search the forums for any info on vintage drop bar replacement but I can't seem to find any. So I hope to get some help from you guys here.

I have a Centurion Accordo RS I use for commuting and the bar's width are too short for me. I read elsewhere during my fit research that the drop bars should be the same or close to the riders shoulder width. My shoulders are 46cm and my drop bars are 36cm. I always seem to experience pain when I ride the Centurion and I used to just rationalize it as not being used to it yet since I mainly ride MTB's. But now that I've purchased a Schwinn Fastback the pain difference is night and day between road bikes. The latter have the least pain in my hands, shoulder, and back. I've dialed the Centurion settings as close to the Schwinn as possible but the hand pain is more pronounce on the Centurion.

The question now is what drop bar can I use for this vintage bike. I've done some shopping but everything seems more geared to newer road bikes and very few vintage bikes. I found the itm super 330, pic below. Would that work? I'm not sure if it'll fit the "hole". Is there a standard size for the clamp for vintage bikes? The site says that the clamp for this bar is 25.88mm. Is that the diameter or circumference? Please help.