I actually putting my project bike back together. It will have mountaing type flat bars....I put them in the stem and they seem really wide..... 23". It might just be that I am used to a lot narrower on my road bike. I am curious, how wide are your handle bars? Thanks

My MTB bars are 27", but im a big wide dude. I like the open chested breathing I get from them.

645mm or 25.4 inches

I use a 23" cut down to 21.5". It's the minimum width that will accomodate my levers/grip shifters/bar ends/ plus room for hands in normal shifting position.

Riser bars force you to go wider due to the bar bends, so add ~1.5-2.0" over "straight" bar minimum width.

Also be aware that many carbon bars can't be cut down, unlike aluminum bars, according to mfg.

Actually the cf can be cut down, except the cutting action tends to delaminate edges of the end of bar - so use a sharp hacksaw blade and be careful. I follow-up cut by putting a heaping tablespoon of mixed slow cure epoxy into bar, then cap bar end with duct tape, place in vise in vertical position overnight, sand dried epoxy for nice finish. Repeat other end. This prevents cf delamination and adds a little crush strength for bar end mounting.

My flat bar is 21.5" wide, and the one on my wife's bike is 23". I left her bar at 23" because her other bike has 25" wide bars, and I didn't want to force such a drastic change. I'll probably cut hers down to 21" before next winter...

23.5" and I spend most of my time on the bar-ends which angle in, so I'm actually at around 21.5" effective width.

shoulder width

23" but will probably cut them down as they feel really wide now.

18in.

But then it's on the commuting bike and there's not much room between those pesky mirrors

Cut'em down. Flat bars are made pretty wide with the thinking that the customer can chop it down, but can't extend it, so longest is best. Ride for a while, chop off 1 cm from each side, ride for a while, chop more if it still feels wide etc.

22"/559mm

wow 420mm drops seem not too wide at all by comparison.

I'll be putting 440 flip'n'chops on my new commuter, so I hope that's wide enough.

22.5", probably soon to become a little less (21" maybe).

I cut my bars down to 22" and installed Cane Creek Ergo II barends. With 23" bars, they always felt too wide and I was always worried I would snag my barends on something. The steering and handling is a lot faster with the cut bars.

21.5" here.

24.5" Bontrager Satellite Plus with barends. They are riser bars and I have twist shifters so am limited in how narrow I can go (but I do like the extra bar space in front for lights, etc). At some point in the future, I will be switching out the twist shifters and will probably chop some more length then.

handlebar.jpg

590mm I've got another flat bar at 570mm that I might chop down and use.

Too wide. Wide enough that going through doors worries me a lot more than it does on my road bike. ( I actually ride through doors as I enter my college. I'm there so early no one else is) Is it really OK to cut bars? Do you use a hand tool or power tool?

It's okay to cut bars, but do a little at a time. Shoulder width is usually the recommended. A pipe cutter works best. You can also use a hacksaw and finish off the edges with a file.