Whats the standard handlebar grip diameter?
 

Are there any general guidelines on guessing what the diameter is where a brake would be attached? Lots of 26mm and 25.4mm bars, it seems, are thinner aside from in the middle, is that a pretty consistent diameter for either?

http://www.sheldonbrown.com/gloss_ha-i.html
Sheldon refers to the 'grip area size' but I dont have good intuition when it comes to bicycles, and I dont know what this means exactly....

Since older bars are likely more complicated, I'm inquiring specifically about the latest ones...

Maybe this wont matter really, I just dont know how well a 25.4mm brake would clamp onto 26mm bars.

Thanks!

The 25.6 & 26mm dimensions are the diameter of the handlebar where the stem clamps on in the center. Most, if not all standard non-road bike handlebars are diameter of 7/8" Grip area refers to that part of the handle bar that is not part of the clapm area... the fat part in the middle where the clamp goes.


A good rule of thumb is that if a bike has slip on handlebar grips, there going to be 7/8", if the bars are wrapped in tape there usually 15/16".

Hope this helped to clear things up.

so to continue this discussion...if i have 26mm bars and i wanted to upgrade to 31.8 would i have to get new grips and shifters and brake levers?

slightly ot, but avoiding a new thread: what's the best way to measure handlebars for brake levers? i'm seeing lever measures ranging from 24.0 mm to 31.8 mm..

No. The "oversized" handlebars are only oversized at the clamp area (and ever so slightly beyond). The rest of the bar diameter will be the same as a 26mm bar.

Best and easiest way is with calipers. They'll give the most accurate, foolproof measurement. If all you have is a ruler, wrap a piece of string around the bar then measure the length of string necessary for that as accurately as possible. Divide that number (the circumference) by 3.14159 and you'll get your diameter. Another crude method is to use an open end wrench and figure out what size fits over the tube and which doesn't. It'll get you in the ballpark at least. I've used this as a last resort when I had no better method available.

Note, when you say "the same as a 26mm bar," you mean to say "23.8mm."

Drop bars, noodle bars, aerobars, triathlon bars are usually 23.8mm where the brakes and grips go, and either 26.0 or 31.8 at the stem clamp. (though some have 25.4 clamp size)

Flat bars, riser bars, north road bars, cruiser bars and butterfly trekking bars are usually 22.2 where the brakes and grips clamp on, and either 25.4mm or 31.8mm at the stem.

If only one dimension is quoted for a bar, it's the stem clamp size. They expect you to know that bars that curve down or forward are 23.8 and bars that curve up, back, or flat are 22.2.

Old ten speeds
 

Some of the steel drop handlebars that came on old ten speeds have the 22.2 grip diameter that is usually associated with mountain bikes. You can still squeeze on a road style brake lever though.

Actually, what I guess I could have said is that "the rest of the handlebar will have the same diameter for clamping brake levers as a 26mm stem clamp diameter handlebar will have." I've never seen handlebars referred to by anything but their stem clamp diameter so that's the terminology I was talking in. I just didn't do the best job of making that perfectly clear as you pointed out :)