(I cross-posted this in the Touring forum, I hope that is OK).

I am building up a new road bike for my wife. She never grew to like drop bars, and wants to try a flat bar. That point is for now non-negotiable.

So, my question is: what width to shoot for?

I know that the best answer is "go with what feels right", but I have found (from previous experience on her road, mountain, and commuter bikes) that she is not very good at telling what needs to change in her setup. Just that she is happy or not happy.

So I am curious what a good starting point is? I have several flat bars that I can cut down, so if we end up going too narrow I can just grab another bar from the parts bin.

She rode 40cm (center to center) drop bars and seemed OK with that. her mtb and town bike both have 660mm wide bars, but i don't think that is going to work well for a road bike that she will be doing a lot of miles on.

The narrowest bars I have are 580mm (from my early mtb days in the 90s). I have the 580mm on there right now and even that seems really wide even for me (even though I run 750mm bars on my mtb)

I was thinking of cutting these down to 550mm. Is that a good starting point for this? I'm using ergon grips with the integrated bar ends.

I am just curious what other people's experience is with this.

Thanks

Get a 29er. Seriously, geometry probably would be better overall. Just run smooth tiress on them, less knobs.

No way. I've used a 29er mtb for road riding, and while it works, the geo is far, far from what I want on many levels .

The bike is done, just need some input on the bar width.

Salsa cowchipper, or something similar, with interrupter brakes, would be a so much better choice.

Riding on the tops it gives her everything a flat barred bike would. And gives so many more options as she learns to ride it.

Otherwise, why not just toss some slicks on her MTB

Drop bars its Shoulder width , roadies don't do straight bars .. you should not cross post.

Live with what ever is comfortable.

No, it wouldn't. I have something similar (cowbell) on my bike. I love them but it does not change anything for her. Some people just don't like drops. She had interrupter levers on her old bike.
Yes, if you are talking about a 400-460cm wide flat-bar with too short of a stem. Otherwise, no it doesn't

Because it is not even remotely close to the same thing.

Any advice on flat bar width?
Thanks.

So explain to me what a flat barred road bike can do that a MTB with locked out suspension and slick tires can't do.

By your post, your wife has an MTB, and a town bike.

The only major advantage to a road bike is that its going to be more aero, and offer multiple hand positions. Of course that is if it has drop bars.

Bastardizing a road bike with flat bars isn't going to offer a substantial improvement in function over what she has.

Any advice on flat bar width?

(I am not interested in the rest of that conversation).

I suspect that not many in the Road bike forum are interested in your thread.

You may be right.

I got useful suggestions for flat bar width in the Touring forum. The bike (2010 Salsa Casseroll) is kind of a light-tourer, anyway. Somewhat along the lines of the All City Space Horse.

Why not look at the measurements of some of the factory-produced flat bar road bikes out there and copy them? I'm sure the good folks at Trek have figured out the appropriate width bars to supply with a FX 7.3 of a given frame size, for instance.

You would think it could be non-negotiable, but in the road forum it never is.

Most riders who prefer flat bars will want to go narrower on the road bike than they would use on a MTB. Go ahead and start with your 580's as is and see how it goes. You can always cut more later.

Old guard roadies are hilarious in their unwavering sanctimony. OP you should post this question in the gravelbiking /rec. cyclocross forum. Their minds are open and experiment with a wide range of setups.

...oh and don't cross post - they take Internets super duper serious around here. Almost as serious as what type of handlebars are on your bike. Important business!

Thanks.
I thought about the gravel/cx forum, but I thought the advice there might skew towards handling on dirt (thus on the wider end of handlebars).

My bad on the x-post. I remember on MTBR you were supposed to keep it to two forums (might be different now). I promise to mend my ways and try to be a better person in the future.

That made me laugh. I knew it was a risk going in.

Good suggestion. I have looked around and seen everything from 560-660mm bars. Not always sure of the reasoning behind them. The wide bars may be due to them being more comfort or dirt oriented, and the narrow ones may be for urban considerations.

Yeah, sort of like crank arm length, I'm sure there's a range they take into account and size the default sizes according to the rest of the bike.

Take a look at some of the more smooth-pavement type hybrid/flat-bar-road bikes from various manufacturers and I'm sure it'll become clear, give-or-take 20mm, where you should probably shoot for.

... Then, once she's ridden it for a while and wants more hand positions, quietly shake your head and add bar ends to her steadfastly-not-drop-bars bike...

FWIW, I am likely going to throw together some parts on my old Traitor Wander that I used as a testing ground for road disc (spoiler, built a Lynskey disc, I'm sold) and use it as a flat bar, road geared singlespeed. For width, I am going to start with a goofy set of Niner... crap, what are they called... they were a bizarre, angled bar that I run on my MTB with some Ergon's I have in the bin. Definitely wide, but I don't really care, and I already have them. I would honestly just find a cheap bar, see if she likes the width or wants more or less, and go from there. Since you have already been VERY well informed that you shouldn't do this for whatever reason, and honestly may be giving the bike slightly different than intended geometry, just try something and see how it goes.

-Trigger Warning: Flat Bar Pic!-

I put the 580mm flat bar on (fairly straight, very little back sweep) and she tried it for a few short rides. It felt awkwardly wide to her when riding.

So I swapped it for a 560mm bar with 15 degrees back-sweep. This seems to be the ticket. Feels comfortable to her. We ended up running it with a 90mm stem.

North Roads bar. Origin8 Tour Classique. Then again, I ride a flat bar adventure/gravel road bike.

Least expensive conversion is to install a mustache bar, allowing you to keep the road levers/brifters. I run my Shimano Tiagra road set on my commuter bike on an Origin8 Tiki mustache bar. Allows me to right fairly upright.

Flat bar road bikes aren't a heresy. Some people don't like drop bars. That said, its more directed to the CX/Gravel Bike and Hybrid Bike forums here.

Keep in mind the Specialized Sirrus is just the flat bar version of the Specialized Roubaix.

Experiment and see what feels comfortable and don't pay attention to the drop bar crowd. It got your wife back to riding her road bike and that's all that really matters.

Get bars so that her hands are 40mm apart when she is in most normal position.
Example: If I rotate my hands from a "on the hoods" position on 40mm bars, to what might be flat bars, I need another 5 mm on each side.
Cut those bars a bit.

Having her hands 40mm (4cm, or 1.6") apart should provide her with excellent control over her bike. I believe this was a thing a few years ago, until the fixie kids grew up

I've put a flatbar on a road bike and the width I made them was the width of my shoulders, which works pretty well; but I wish I had made them just a bit wider because you will want to add a bike computer and light. The shifters and brake levers take up more space than you might think.

BTW, I also have a bike with drop bars and I find flat bars are much better in a number of ways. First, you can ride with greater stability. This is why mountain bikes have flat bars. Second, your hands are much more comfortable. Ergo grips are really nice on the hands. My palms ache when I ride the drop bar bike. Third, the "aerodynamics factor" is not really a factor. My flat bar puts my hands in a position lower than the hoods on my drop bar. This gives the flat bar better aerodynamics than the drop bar ridden on the hoods or tops. Finally, I always use a mirror when riding no matter which bike I ride. The flat bar accommodates a mirror much better than the drop bar.

Good luck.

That is the best answer.

Put the widest bar you have on the bike. Then have her ride the bike around starting with her hands at the end of the bars. Little by little have her move her hands from the ends of the bar towards the stem. Wherever her hands are on the bar that feel the most comfortable...mark it and cut.