Noonievut

I know there are different handlebar diameters where the stem clamps the bar. My question is whether the other areas of the bar (alloy road bars, like FSA) have different diameters between brands and models. I thought these FSA Omega Compact bars I bought for one bike were same as bars on my road bike (same make and model, bought close to 10 years ago), but they feel like a much smaller diameter. I’m guessing it’s the bar tape, however, I’ve had this same tape and it was way thicker feeling on a previous handlebar in had for this bike.

Andrew R Stewart 

Drop bar diameters range from 22.2 to 24.5mm aprox. for common ones. A little while ago some brand offered a bigger diameter but I haven't seen them any longer. No surprise as the levers being made by other companies would have to also be bigger in size to fit. 22.2mm is the "classic" steel bar diameter with the stem clamp area expanded to 25.4. 23.5/23.8 is the "classic" Al bar size. Note that both will reduce at the curves as when a tube is bent it usually is deformed from a true round shape.

Bar wrap can vary in it's thickness and if added layers are wrapped can be rather large in diameter. Andy

KerryIrons

The shifter lever clamps have to fit the bars, so they are all the same size away from where the stem clamps the bar. Some bars are a bit tricky to slide the shifters on because aluminum ones get distorted when bent, but other than that they are the same all the way to the bulge/flare between the shifter mounting point and the stem.

Noonievut

I’m now thinking that in addition to how the tape was applied and it’s thickness, the older FSA bars are flatter on top. Hard to tell with tape on there and each bar has a gel padding beneath the tape.