The skinny on handlebar width
In the first article of this series, we discussed some of the issues involved in finding your optimal road handlebar. In the rest of the series, we will have a look at the different dimensions of the drop bar and how they affect fit. This article concentrates on handlebar width. Future articles will explore reach, drop and shape.
For the remainder of this article we will be focusing on road handlebars. Some, but not all, of the points I’ll make carry across to flat handlebars as well.
What is handlebar width?
Handlebar width is a measurement of the bars perpendicular to the stem. As is so often the case with bicycle measurement, there are a number of different ways to measure handlebar width. One common approach is to measure at the forward most point on the bars, from the centre of each drop. Be aware that there are other methods – for example measuring from the outside of the drops. Or, as the image below shows, the measurement can be made at the end of the drops. If purchasing new bars, you need to make sure you know how the manufacturer measures their bars and adjust accordingly.
Bars typically come in 36 to 44 cm widths, in 2 centimeter increments. There are exceptions to this rule, but they can be hard to find.
The affects of handlebar width
For all the attention that most pay to handlebar width, you would be forgiven for thinking that it didn’t have much impact. In reality, there are some substantial impacts and the wrong choice could lead to discomfort or injury.
Mechanical
Starting with the purely mechanical, handlebar width can change the steering on a bike. The distance the end of the bar moves for a given change in angle of the front wheel is a function of the bar width (among other things). A wider bar might make the bike feel like it has slower steering. A narrower bar can make the bike feel twitchy. I emphasize the qualifiers here as people seem to have a range of sensitivity. Some don’t notice any difference where others notice a lot. Any change is also likely affected by other factors such as the head tube angle and the trail of the bike in question.
Handlebar width also can change the amount of force that needs to be applied to the bars to move the wheel. The amount of force required to move the bar is inversely associated with the amount of distance the end of the bar moves for a given change in angle of the front wheel. The change is not huge across typically available handlebar widths, but if you are having to muscle an uncooperative bike around corners, wider bars might help. Wider bars can also help if the fork or handlebars are carrying a lot of weight (handlebar bag, front panniers etc.).
Aerodynamic
Aerodynamics can be influenced by handlebar width. When considering the bike alone, narrower handlebars reduce drag as there is less to catch the wind (all else being equal). When considering the bike and rider as a system, things become less clear cut. Narrower bars can reduce the frontal area of the rider, reducing drag. However if the bars are too narrow, many riders compensate by widening their elbows, actually increasing their frontal area compared to wider bars.
The width of the handlebars can also affect how efficiently a cyclist can breath. Bars that are too narrow can lead to narrowing of the shoulders and trunk flexion that can hamper breathing dynamics. The accessory breathing muscles in the neck and shoulders are compromised. In addition, the main breathing muscle, the diaphragm, will have difficulty descending which is required for optimal inhalation and exhalation.
Comfort and injury
Finally, handlebars can play a substantial role in comfort and injury risk for a rider. Incorrect bar size can lead to hand, wrist, shoulder, neck and upper back issues. These issues can range from minor muscle discomfort through to neurological conditions. For example with bars that are too narrow there is a tendency for riders to collapse inwards at the wrists. This alters the upper limb alignment and potentially leads to adverse nerve tension through the arms and wrists. In fact, this neural tension could be tracked a lot further up to the compromised space between the neck and collar bone.
What are the consequences of bars that are too wide?
Some of the possible problems arising from bars that are too wide include:
- Compromised handling (slow steering).
- Increased aerodynamic drag (increased cross sectional area).
- Increased stress on wrist, shoulder and neck muscles and connective tissues.
What are the consequences of bars that are too narrow?
Some of the possible problems arising from bars that are too narrow include:
- Compromised handling (twitchy steering, harder to turn at speed).
- Increased aerodynamic drag (if elbows go out to compensate for the narrow bars).
- Increased stress on wrist, shoulder and neck muscles and connective tissues.
- Compromised breathing.
How do we find the right width for you?
So how should you go about choosing handlebar width? One traditional approach that is quite common is to measure the width of your shoulders. Or more precisely, the distance between the tips of your two acromions. In my experience this is not ideal. It might give an idea of the suitable starting point for trialing handlebar width, but it fails to take into account a whole range of factors.
At Winning Position we start each bike fit by discussing with you your riding experience. This includes talking about what discomfort or injuries you might have. We look at you in your existing position and observe things like whether your wrists are cocked, how you hold your shoulders and what your frontal profile looks like.
Once we get you on the dynamic fit bike, we can then start to play with handlebar width. As mentioned in the initial article in this series, we use Profile Design sizing bars so that we can very quickly change between different widths. We get to trial different widths and find the one that is best in combination with your fit.
Not everyone who I fit needs to change the width of their handlebars. In fact, the proportion of clients who change bars is quite small. One of the things I keep in mind when fitting is that I want to avoid unnecessary expense for my clients. If the existing bars on your bike will work ok, then let’s leave well enough alone. Even if different width bars might lead to a marginally better position. But for those who are suffering pain or looking for every advantage, then a change in bar width can be priceless.
