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.
Your meseurement of pedal heights are all wrong. Obviously, powermeter pedals are THICKER than standart pedals… So you’ll need to move your saddle HIGHER!
Hi,
Which two pedals are you interested in?
Thanks,
Yes, I think you need to re-think this. My new faverio assioma pro mx have a stack height of 11.2mm but are significantly thicker that my shimano spd xtr pedals, which have a stack height of 15.1mm… So that makes no sense.
Using my calipers on the pedals I need to actually raise my saddle about 3mm, rather than drop by 5.1mm like your chart.
I guess each company is not measuring the same way. The assioma pro mx’s seem to be from 11.2mm from the center of the axle to the base of the pedal. The shimano spd xtr’s if measured the same way come to approx 8.5mm measuring just now.
Shimano measures center axel to top pedal, not center axel to top cleat