How to Use The Bike Stem Calculator

Stem length and angle are interrelated, and altering one can impact the other.  Generally when looking to change your stem there are two measurements you’re interested in:

• How will this impact my stack (how might the handlebars are)
• How will this impact my reach (how far away the handlebars are)

Our stem calculator helps visualize and compare the reach and stack between stems, aiding in finding the right fit quicker. The tool is set up for you to input your current stem as the Red stem, then input the dimensions of the stem you’re considering as the Blue Stem. At the bottom your will see your output of the differences in stack and reach.

You will also note that the tool requires the input of your bikes head tube angle, as well as the number of headset spacers you are using as these are critical inputs to understand how your stem will interact with your bike.

Stem Length

Measured from the centre of the steer tube to the centre of the handlebar clamp, stem length primarily contributes to your reach to the handlebars. Longer stems move your body forward, generally increasing pressure on the front wheel while contributing to a slower, more indirect steering feel. Conversely, shorter stems lead to a more upright position, shifting pressure towards the rear wheel.

Based on the above, it is generally found that longer stems are found on road bikes, while the shortest stems are found on more gravity oriented mountain bikes (e.g. enduro and DH), with everything else in between.

Stem Angle

The angle of the stem relative to the steerer tube influences handlebar height and your riding posture. A higher stem angle results in a shorter reach (given the same length), facilitating a more upright position and reducing front wheel pressure. A lower stem angle, on the other hand, extends your position, increases front wheel pressure, and creates a more stretched-out posture.

Stem Length vs. Reach

It’s essential to note that stem length is not the same thing as reach. Reach is measured in strictly the horizontal plane, whereas due to the angle of the steer tube and stem, stem length rarely translates perfectly to reach.

Understanding these dynamics is key to optimizing your bike fit and ride quality. Our bike stem comparison tool is designed to guide you through these choices, ensuring you find the perfect stem for your cycling needs.

Typical Stem Lengths

Selecting the right stem is crucial for achieving the ideal bike fit. This guide provides an overview of common stem lengths across various bike types based on bike size. While there is no rule for stem length as they should be tailored to the rider and bike, these tables provide a quick reference guide to see if you might be contemplating a change well outside the norm.

Road Bikes

In road cycling, stem length is pivotal for achieving a responsive yet stable ride. Road bikes, with their steep head angles and narrow handlebars, have inherently quick steering. Longer stems help balance this out by providing less directness in steering, enhancing stability and control, especially at higher speeds. The table below provides common stem length ranges and angles for road bikes.

Gravel Bikes

Gravel bikes, blending road and mountain bike characteristics, require unique stem length considerations. Though gravel bikes are broadly more similar to road bikes they often borrow slightly from mountain bike geometry, specifically lengthening the reach of the frame to improve stability over rough terrain. The result is the need for slightly shorter stem length to improve maneuverability and control on diverse surfaces. Below are common stem sizes for gravel bike.

It’s important to note that gravel bikes occupy a large range of geometries, some more closely resembling road bikes while others more closely resembling mountain bikes. In general, the more road oriented bikes will lean towards the longer end of the stem ranges, while the bikes focused on more technical terrain will lean towards shorter stems.

MTB XC

XC mountain biking emphasizes climbing and agility, necessitating a distinct approach to stem length. While shorter than road or gravel bike stems, XC stems are often longer than those in other mountain biking disciplines to aid in the riders weight shifting forward during steep climbs. The table below provides common stem size ranges for XC bikes, balancing climbing efficiency with responsive handling.

MTB Trail & Enduro

Trail and enduro mountain biking often target shorter stems to balance out the the slacker head tube angles and wider handlebars, which inherently increase stability and slow down steering. This combination enables the use of shorter stems without losing control, enhancing handling in technical sections and aggressive descents. The table below reflects these design considerations, providing stem length options for the unique demands of trail and enduro riding.

Stem choice for Trail and Enduro MTB is perhaps the most personal of any bike type as handling is the primary driver of decisions. Unlike other disciplines which place more importance on riders seated position, stem choice for these disciplines is primarily driven by the handling of the bike when out of the saddle.