If you buy a new set of power meter pedals, chances are you need to make an adjustment to your seat height in order to retain a proper fit on the bike. In this FAQ, we’ll explain why and exactly what you need to do!
Proper Seat Height
Your correct seat height is determined by your preferred knee angle through the clock that is the pedal stroke. Most bike fitters will get a knee angle connecting the ankle-knee-hip bones when your pedal stroke stops near 6 o’clock. This is frequently 140-145 degrees.
Stack Height
Stack height is the measurement from the center of pedal spindle to the top of the cleat. Almost every pedal has its own unique stack height. This is why, when you buy a new set of power meter pedals, it’s important to know how your stack height changes so you can make the needed change to your seat height.
For example, if you change from a DURA-ACE 9100 SPD Pedal to a Garmin Rally RS Power Meter Pedal, you would need to lower your saddle by 2.4 mm. This is because the the DURA-ACE pedal has a stack height of 14.6 mm while the Garmin is 12.2 mm).
Power Meter Stack Height Comparison Table
In order to make things easy, we built the table below which includes some of the more common ‘normal pedal to power meter’ changes. Please note that all other variables (saddle, saddle tilt, crank length, etc.) remain constant.  This is just the math and should be taken as a base starting point. A + means your seat should be raised which a – means lowered. The amount is in millimeters.