Sweat the Small Stuff
There are many factors to consider when buying, building, or making an upgrade to your bike. It is often said that best upgrade to a road bike is lighter wheels, as they contribute significantly to aerodynamics and are the best place to save weight. One of the most overlooked decisions, however, is about the stem.
Many tend to focus most of their attention on the frame, wheels, and groupset. While upgrading to carbon wheels or a lightweight frame can make a huge difference, one thing that is often neglected is how much a change to a smaller part of the bike can bring. In this article, we will explore how bike stem length affects the riding experience and what may be right for you.
What Options are Available?
When deciding which stem length is correct for you, it is important to decide what kind of riding you do. Stem length plays a significant role in comfort, stability, responsiveness, and aerodynamics. The most common lengths for road bike stems is 100mm and 110mm, but sizes from 80mm to 140mm are widely available. They offer a balance between all of these factors. Let’s take a look at each riding characteristic and how stem length affects it.
Without a doubt, an upright position is the most comfortable for the majority of riders. This can be achieve by certain relaxed frame geometries. It can also be influenced by stem length. A shorter stem encourages a more upright riding position as the rider does not need to reach so far. You would be surprised by how much a few centimeters can make a difference. For more stability, it is recommended to choose a stem close to 80mm in length.
For some riders, having a stable ride is very important. This is especially true while descending or in crosswinds. Having the extra control can inspire confidence in the rider. It can make riding safer. Professional cyclists tend to choose longer stems. A lot of their racing is done at high speeds, where stability and control are very important, especially when in the peloton, where the often ride just inches from one another. For better control and stability, a longer stem is recommended.
The role that the stem plays in the responsiveness of a bicycle is nothing to be overlooked. A shorter stem changes the weight distribution in relation in relation to the front tire. While this isn’t ideal for high speeds or descending, a short stem can be very beneficial in city riding where speeds are slower and there are many obstacles.
The last factor we will touch on in this article is aerodynamics. At higher speeds, the largest force on the bicycle is that of wind resistance. The faster you go, the more of an effect it has. A doubling in speed translates to a four-fold increase in aerodynamic drag. In order to combat this, there are many things you can do. By far the largest culprit keeping you from going faster. It is said that the rider is responsible for roughly 80% of the aerodynamic drag.
In order to combat this, the best upgrade is clothing and riding position. Riding position can be improved by reducing the frontal area of the rider. One way this can be accomplished is by putting the rider into a more aerodynamic position. A longer stem can help do this.
What About Stem Angle?
To make things even more complicated than just looking at stem length, there is also the factor of stem angle. There are so many options available. Few stems have a stem angle of 0 degrees. Most have a stem angle of between 6-18 degrees, those some are even more so. One reason for having an angled stem is that the steerer tube on bicycles is angled. If the stem is as well, it can be parallel to the ground, giving the bicycle a good look.
They can also serve many other purposes. Just like how stem length can influence aerodynamics and comfort, so can having a different stem angle. Stems can be flipped. For example, a 17 degree stem could be flipped to put it at a -17 degree angle. One stem can provide a very different ride experience depending on its orientation. A stem angled downward can make the bike more aero, and one angled upward can offer more comfort.
Other Factors to Consider
When choosing a stem, besides the length and angle, there are other differentiating factors such as the material it is made out of and whether or not it is integrated. In some cases, the rider doesn’t have much choice as their bike might come with an integrated stem and handlebars. In reality, there is no one-size-fits-all. Many riders will choose to even get a professional bike fitting to have a more comfortable and tailor fit riding position. This can make a big difference.