Dialing It In: The Impact of Stem Size on Comfort and Performance in Cycling

When it comes to achieving the perfect bike fit, the size of your bike's stem is a critical component that often goes overlooked. The stem, which connects the handlebars to the steerer tube of the fork, plays a significant role in determining your overall riding position, comfort, and performance.

The Role of Stem Size

The stem's length and angle directly influence your reach and handlebar height. These factors can significantly impact how you feel on your bike and how efficiently you ride.

1. Comfort and Riding Position

The right stem size can make a world of difference in your comfort. Here's how:

• Reach: A stem that's too long will stretch you out, putting strain on your back, shoulders, and neck. Conversely, a stem that's too short can make you feel cramped and place excessive pressure on your hands and wrists. The ideal stem length allows you to maintain a neutral, relaxed position on the bike.

  
  

• Handlebar Height: The stem angle, or "rise," affects the height of your handlebars. A higher handlebar position can alleviate pressure on your lower back and provide a more upright, comfortable riding position. A lower handlebar position, achieved with a stem that has a negative rise, is often favored by more aggressive riders seeking an aerodynamic posture.

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2. Performance and Handling

Stem size also plays a crucial role in your bike's handling and performance:

• Steering Precision: A longer stem provides more stable steering, making it suitable for high-speed descents and smoother roads. However, it can make the bike feel less agile. A shorter stem offers quicker, more responsive steering, which is beneficial for technical terrain and tight corners.

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• Power Transfer: Your position on the bike affects how efficiently you can transfer power from your legs to the pedals. A well-fitted stem ensures that you're in an optimal position to maximize your power output, whether you're sprinting, climbing, or cruising.

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Finding the Perfect Stem Size

Getting the right stem size involves a bit of trial and error, but here are some tips to help you find the perfect fit:

1. Start with Your Frame Size: Your bike's frame size is the foundation of a good fit. Ensure that you're starting with the correct frame size for your body.

   
   

2. Assess Your Reach: When sitting on your bike, you should be able to reach the handlebars comfortably without feeling too stretched or cramped. Your elbows should have a slight bend, and your shoulders should be relaxed.

   
   

3. Experiment with Stem Lengths: 

   1. DIY: If you're unsure about the perfect stem length, many bike shops offer adjustable stems or a variety of stem lengths for you to test. Start with a neutral length (around 90-110mm) and make adjustments as needed.

      
      

   2. Have the Bike shop Bike Fit: This can help your further dial in your stem size and get you into the right spot. 

      
      

   3. The PT Bike Fit: This may be surprising but we take a look at the cleats and saddle first prior to looking at your stem. This allows us to get your main points of contact in order prior to looking at the stem. Adjustments made at the cleats and saddle can make it easier to comfortably reach those handlebars. Lastly, if stem size needs to be addressed, changing the size longer or shorter can make riders more comfortable. 

      
      

4. Consider Your Riding Style: Think about how you ride. If you prefer a more relaxed, upright position, a shorter stem with a positive rise might be ideal. For a more aggressive, aerodynamic position, a longer stem with a negative rise could be better suited. Consider if you need a shorter stem for more responsive steering conditions or a longer stem for more flow. 

   
   

PT Bike Fit

For the most accurate fit, consider investing in a PT bike fit. Our physical therapist will take detailed measurements and assess your riding style to recommend the perfect stem size and angle for you. They can also make other adjustments to ensure that your bike is tailored to your unique needs and goals.

To dial in your stem size we use a salsa stem sizer: This device can attach to your steering tube and handlebars and identify the best angle and length of your stem that is most comfortable for you. 

The goal for your stem size is to have a flat mid-low back position and shoulders in a 90 degree position. 

Conclusion

Stem size is a vital component of a good bike fit, affecting both your comfort and performance. By taking the time to find the right stem length and angle, you can enhance your riding experience, improve your handling, and maximize your power output. So, next time you hop on your bike, remember that dialing in your stem size can make all the difference.

Happy cycling! 🚴‍♂️🚴‍♀️

Resources: 

1. Powlison S. Bike Geometry Charts & How They Work (Stack & Reach Measurements). The Pro's Closet. Published January 28, 2020. Accessed May 15, 2025. Available from: