What is the proper way to measure handlebar width for a road bicycle with drop handlebars? But do you measure from the front or the back? Most sources say from acromion process on shoulder to acromion process. I've seen it both ways (here and here). If I measure my wife from the front, she's 38 cm. From the behind-- counting the curvature of her back -- she's 41 cm. Which measurement do I use?

FYI, the acromion process is a $5 word for the bump on your shoulder. See here and here.

I've tried to do my homework but if this has been described elsewhere please let me know and I will RTFM.

Thanks in advance.

I have always measured shoulder width from the front, but it's a reasonable question.

However comfort plays a role too, so I would have her try 38 and 40 and see which feels more comfortable.

center of the left hood to center of the right hood

Measure the width of your shoulders and add 2 inches was the general rule of thumb from what I heard

Measure the body from the front of the body, but keep in mind that it's just a guideline and all bars are not measured the same. All brands measure the width at the ends, but some measure center to center and others measure outside to ouside, which makes them about 2cm narrower than the same size measured c-c. Also, there are some bars that place the brake hoods 1-2cm narrower than the width measured at the ends and it's really the brake hood c-c measurement that's most important. I owned some FSA compact bars that were 40cm at the ends, but the brake hood spacing was only 38cm.

Manufacturers usually take drop handlebar width measurements in one of three ways. From most to least common these are:

1. center to center at the ends of the bars
2. outside to outside at the ends of the bars
3. center to center where the brake levers mount

Just keep the above in mind once you have a width in mind and check the manufacturer's measuring method to make sure the actual width will jive with your/your wife's expectations.

Thanks for all the thoughtful replies. In the end I think datlas response is what I followed. Out for a walk we stopped in our LBS and saw a Salsa Short and Shallow Moto Ace. She picked up a 38 and a 40 and went with the latter. A deal clincher for her was the ergonomic bump.

Looks like there is a limit to buying thing over the web by spec only.