Is handlebar diameter standardized?

[fredd]

Possibly a stupid question, but I find that my large hands prefer thicker handlebar tape because it make the handlebar effective diameter larger.

Is handlebar diameter standardized? Or are there thinner and thicker bars? Just to be clear, I'm talking about the diameter of the tops/drops, not the clamp diameter.

Also, I know that there are extra thick track bars, but those don't have to deal with hoods.

[mhespenheide]

They're semi-standardized but not fully standardized.

For vintage bars, there were standards for clamp diameters of 25.4mm, 26.0mm, and 26.4mm. I'm going to assume that you're not asking about those.

For modern bars, the standard clamp diameter is 31.75mm; most companies round that up to "31.8mm" but for some unknown reason Deda rounds that down to "31.7mm". They're the same in practice. There's also a less-common standard clamp diameter of 35.0mm; that's mostly from Deda. They call it "Trentacinque", Italian for thirty-five. Some other companies use the 35.0mm standard as well, frequently in carbon handlebars.

As to the tops, some handlebars taper down from the clamp area immediately and have skinny tops, while others hold a large diameter across the tops and then taper at the bend. All bars need to taper before the location where the brake levers are mounted, because that dimension is standardized.

I can say that Bontrager makes some 31.8mm bars that keep their width across the tops and they're nice in the hand. Or at least I like them.

You could also go on eBay and select the clamp diameter you're looking for and then just check visually for bars that don't obviously taper right next to the clamp.

You could also look for some of the "aero" handlebars that are flattened out across the tops; some people like the extra grip area given by the flatter section.

[GregL]

The Ritchey EvoCurve bars definitely have fatter, flatter tops. I've found the shape to be comfortable for my large-ish hands.

Greg

[benb]

I think you could say standardized but not at ultra high tolerances, that seems to be wear some incompatibility comes from. But a lot of the designs on bikes have that built in.

I wonder how much sample to sample variation there is. You'd have to work at a factor or distributor to get much of a picture.

[prototoast]

With the exception of some oddball handlebars from Canyon, the drops are all standardized because you have to be able to slide a standard brake clamp over them.

As other have mentioned, for the tops, you have all sorts of options ranging from round/oversize, to ovalized, to all-out aero.

In the budget category of bars, I really like the Zipp Service Course bars for larger, ovalized tops.

[cgolvin]

Thomson bars also hold a larger diameter from the clamp before tapering at the bends.

[David Kirk]

Most modern bars are the same diameter at the stem clamp..and they are also the same diameter from where the levers mount to the bottom of the drops. So the only place they typically vary is between the lever area and the stem.

dave

[Gasman1440]

Interesting thanks