TABLE OF CONTENTS
Overview
Step-by-step guide to replacing the left-side power meter. Estimated time – 15 minutes
Tools required
- 15 mm pedal wrench or narrow 15 mm open-ended wrench for pedals with wrench flats, or correctly sized hex key for all other types.
- 8 mm hex key
- Torque wrench with 8 mm hex bit (torque range up to 57 N⋅m / 42 ft⋅lb)
- Philips head screwdriver #0
Replacement parts
971-9509, LEFT CRANK, POWER SENSOR, W/CRANK BOLT, MULTI-POS
Replacement instructions
Unplug bike
Before starting the repair, remove the power connector from the bike behind the rear leg.
Remove the left pedal, if installed
Using a 15 mm pedal wrench (or corresponding hex key), remove the left-side pedal by turning it clockwise, then set it aside for reassembly later.
Remove the left-side power meter
Position the crank arm in the three o’clock position. Using an 8 mm hex key, turn the center crank bolt counter-clockwise to remove the left-side crank.
TIP: The crank arm attaches using a self-extracting bolt. This means that the pressure to unscrew the bolt will increase as it pushes the crank arm off the bottom bracket spindle. This is normal. Just keep rotating the bolt until the crank arm is fully removed.
Install the new left power meter (971-9509)
If there is a pedal installed on the right-side crank arm, it will naturally rest downward in the 6 o'clock position. If no pedal is installed, position the right-side crank arm in the 6 o’clock position.
Position the new left-side crank arm in the vertical position and install it onto the bottom bracket. Make sure to align the crank arm to the splines of the bottom bracket 180 degrees from the right-side crank arm.
Holding the left crank arm in place, use an 8 mm hex key to begin tightening the bolt clockwise back onto the bottom bracket splines. The bolt should thread on easily and not require excessive force to begin threading in. If any binding or excessive force is encountered, unthread the bolt and begin again to ensure no cross-threading occurs.
Once the crank bolt is smoothly tightened to finger tight, you will feel the resistance of the bolt increase. This is normal. At this point, turn the crank arm to the 9 o’clock position for more leverage and continue.
Once relatively tight, set your torque wrench in the range of 52-57 N·m (38-42 ft·lb) and completely tighten the bolt until the torque wrench clicks.
ATTENTION: Check behind the crank arm to ensure no gap exists between the crank and bottom bracket. It is possible for this torque range to not fully seat the crank arm. If the crank arm is not fully seated, continue tightening the crank arm on until no gap is visible.
Reinstall the left pedal, if previously installed
Hand-thread the left-side pedal into the corresponding crank arm length hole (matching the length selected on the right side) by turning it counter-clockwise.
Use a 15 mm pedal wrench (or corresponding hex wrench) to tighten the pedal until it is snug (torque specification may vary by pedal manufacturer).
Plug the bike into external power
Re-plug the bike into external power.
Configure the power meter in the Stages Cycling app
After completing the physical installation, the new left-side power meter must be paired to the bike to complete the installation. Using a size #0 Phillips head screwdriver, slightly unscrew the battery cover and remove the plastic battery isolation strip, then re-tighten the battery cover (tighten until snug, do not over-tighten).
- Open the Stages Cycling app. Ensure the SB20 is powered on and the new power meter is awake (rotate the crank arms if the power meters have not been moved in over 5 minutes).
- Click the Devices icon > Select your Stages Bike SB20 or add it as a new device > Power meters.
- Tap the power meter IDs to bring up the power meter configuration menu.
- Locate the ANT+ ID sticker on the inside edge of your new left power meter and input it into the Left ANT ID field.
- Select OK. The app will begin pairing your new power meter. This can take 30 seconds or longer.
- The bike will disconnect and reconnect from the app during the pairing process. Once the bike has reconnected, position the cranks in the vertical position and tap the Zero Reset button.
- After completing the zero reset, you can exit the app and your bike is now ready to ride.
Enjoy your ride.