Shimano's HollowTech crank system is known as one of the lightest, stiffest cranks on the market. By using a large hollow one-piece spindle and drive arm, the system transfers power from the pedals to the rear wheel efficiently and effortlessly, improving your pedalling performance. You can take advantage of this system by installing it on your bike at home, and save time and money over having a mechanic install the system at your local bike shop.
- Skill level:
Things you need
- Bottom bracket wrench
- HollowTech crank and bottom bracket
- Hex wrench set
- Shimano spindle-wrench
- Crank puller
- Rubber mallet
Lean your bike on its kickstand, in a dedicated work stand or on its handlebars and seat so you can perform the crank replacement procedure without accidentally knocking it over.
Shift into the lowest front gear by pressing the downshift lever of the left shifter. Pull the chain off the chain wheel and let it sit around the bottom bracket of the bike. Use a hex wrench to loosen and remove the crank mounting bolt on both crank arms.
Thread the outer part of the crank puller into the drive-side crank arm by hand. Be sure that the tool interfaces correctly with the threads, as crank threads are surprisingly easy to strip. Spin the arm of the tool clockwise to force the crank arm off the bottom bracket spindle. Remove the nondrive-side crank arm the same way.
Loosen and remove the drive side of the bottom bracket by turning it clockwise--the drive side is reverse-threaded--with a bottom bracket wrench. Remove the bottom bracket from the frame. The entire spindle and drive side cup should come out in one piece. Loosen and remove the nondrive-side bottom bracket cup by turning it counterclockwise with the bottom bracket wrench.
Install the drive-side HollowTech bottom bracket cup by threading it into the frame counterclockwise. Use a bottom bracket wrench to tighten the cup into the frame. Install the nondrive-side HollowTech bottom bracket cup by threading it into the frame clockwise. Tighten the cup in the frame using a bottom bracket wrench.
Slide the spindle of the HollowTech crank, attached to the drive side crank arm, through the opening in the drive-side bottom bracket cup. The spindle should stick out of the nondrive-side cup. Pull the chain off the bottom bracket of the bike and onto the small chain wheel. Tap the crank arm into the cup lightly with a rubber mallet to be sure it is secure.
Attach the nondrive-side crank arm to the end of the pedal spindle sticking out of the nondrive-side bottom bracket cup. Thread the black plastic spindle cap into the end of the spindle from outside the crank arm. Use a Shimano crank spindle wrench to tighten the spindle cap securely. Tighten the 5mm hex bolt on each side of the nondrive-side crank arm to secure it tightly to the spindle.
Remove the pedal from your old drive-side crank arm using a 15mm wrench. The drive-side pedal is reverse-threaded, so spin the pedal spindle clockwise to loosen it. Attach the pedal to the new HollowTech drive-side crank arm by threading it in counterclockwise and tightening it using a 15mm wrench. Remove the pedal from your old nondrive-side crank arm by turning the pedal spindle counterclockwise. Attach the pedal to the new HollowTech nondrive-side crank arm by threading it in clockwise and tightening it using a 15mm wrench.
Take your bike for a test ride. Listen for popping or creaking from the bottom bracket. If all is quiet, the crank has been installed correctly. If the bike makes strange noises when you step on the pedals, there may be frame or bottom bracket issues that need to be diagnosed by a certified bicycle mechanic.
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