The newest addition to my stable is a late-80's Centurion Ironman that is a blast to ride and very comfortable, but I continually feel like the bars are too narrow for spacing of my arms. I have read that some of the older bikes have 26.0 or 26.4 size stem clamps, how can I tell?

On the bar it says: Nitto B115 420. Should I assume these are 42cm bars? I have fairly broad shoulders, and I want to move up to a 44cm handlebar.

Also, why does it seem that any newer 60cm bike I ride feel like I am stretch out beyond the point of comfort while any of my older bikes feel like they are shorter?

Probably a 25.4 MM handlebar in a bike that old. Roger

I have an '84 Centurion ProTour (touring bike), the original bars were very narrow 38 or 40 on a 59/60cm frame. Just the style from Japan, me thinks, but I grew to like narrow bars and still ride narrower than most people my size. Any decent shop should have a set of calipers to tell you the exact diameter of the bar, why guess? - it may not be original.

As to being stretched on a modern bike, determine the TT length you are most comfortable with and stick to it. Watch out for set-back seatposts and unusual stem lengths which might change your position. With so many mfgs in the industry there is bound to be a significant range of variation in determining sizes.

That Nitto is a 42 cm (420mm). I'd suggest thinking about 46's as well as 44's.

The "most comfortable with" would have to be this bike. My KHS would be a distant second. I will have to get that top tube length in the morning. Should I measure the stem length as well or does that not matter as much?

I completely forgot about using a set of calipers. I have a set I use for wrapping fly rods that will do the job quite nicely. I believe Jenson has a set of 25.4mm,45cm that I will get if it is the right size.

Weird. I measured the circumfrence twice and got 81.5 (25.94mm diameter). I measured the diameter with my calipers and I got 26.0. I would have thought it was the 25.4 like a lot of the Nitto bars that are currently sold...

Yes, measure your stem length 10 - 12 cm is typical. Also look at your most comfortable bike and see where the saddle is mounted on the rails (ie, all the way forward, all the way aft, kinda in the middle). Some people measure from the tip of the saddle to the handlebars. Good luck.

I have a set of Nitto Olympiade bars also 26.0. Methinks back then Nitto was trying to copy the Italian road standard of 26.0. Nowadays they'd rather go with the Japanese/mtb size of 25.4 (I think MTB is 25.4 anyway. I don't know jack about MTB though). Of course I'm sure they also made 25.4 back then, too.

A lot of Japanese manufactured drop handlebars in the 80's tended to be a narrow 40 cm. That was, for whatever reason, the standard back then and yes, they could be a bit narrow for some riders.