The Shimano FC-5700 [paid link] crankset is a popular choice among road cyclists for its durability, smooth performance, and high-quality design. However, one of the most critical aspects of maintaining this component is ensuring that the crank arm bolts are correctly tightened. Over-tightening or under-tightening the crank arm bolts can lead to various issues, from performance degradation to potential damage. This guide will walk you through the precise steps of crank arm bolt tightening for the Shimano FC-5700 [paid link], helping you achieve optimal power transfer and longevity for your bike.
Tools Required
- Torque wrench [paid link]
- Shimano FC-5700 [paid link] crankset installation tool (or suitable crank arm tool)
- 8mm Allen key (or appropriate tool for the crankset bolts)
- Grease (preferably a bike-specific anti-seize grease)
- Rags or cleaning cloth
- Torque specifications sheet (for Shimano FC-5700)
Understanding the Importance of Crank Arm Bolt Tightening
Properly tightening the crank arm bolts on your Shimano FC-5700 crankset is crucial for maintaining a stable and efficient pedaling platform. Crank arm bolts secure the crank arms to the spindle of the bottom bracket. When these bolts are not tightened correctly, it can result in wobbling or, in extreme cases, the crank arm detaching from the bike altogether. Tightening the bolts too much can damage the crankset or bottom bracket, while loose bolts can cause dangerous instability and power loss.
To get the best performance from your Shimano FC-5700, the crank arm bolts must be tightened to the manufacturer’s specifications using the right tools and techniques.
Step-by-Step Guide to Tightening the Crank Arm Bolts
1. Preparation: Clean and Inspect the Crankset
Before adjusting the crank arm bolts, clean the crankset thoroughly. Use a rag to remove dirt and debris from the crank arms and bottom bracket area. Inspect the crank arms and bolts for any visible damage, including cracks or wear. If any damage is noticed, replace the damaged parts before proceeding.
2. Apply Grease to the Threads
Apply a thin layer of grease or anti-seize lubricant to the threads of the crank arm bolts. This prevents rust, corrosion, and binding, allowing you to tighten the bolts smoothly without over-torquing them. Be sure not to apply too much grease, as excess grease can attract dirt.
3. Insert the Crank Arm Bolts
Place the crank arm bolts into the threaded holes on the crank arms. Ensure they are aligned correctly and do not cross-thread. The Shimano FC-5700 crank arms typically use an 8mm Allen bolt, so use the appropriate tool to fit the bolt heads securely.
4. Initial Hand Tightening
Begin by tightening the bolts by hand. Turn them clockwise until you feel resistance, ensuring they are seated properly. Do not use excessive force during this step, as hand-tightening is only meant to position the bolts in place.
5. Torque the Bolts Using a Torque Wrench
Now that the bolts are hand-tightened, you need to use a torque wrench [paid link] to bring them to the correct torque specification. Shimano recommends a torque setting of 12-14 Nm for the crank arm bolts on the FC-5700 crankset. This is an essential step because too little torque can cause the bolts to loosen, while too much can damage the crank arms.
Attach the appropriate size Allen key or bit to your torque wrench [paid link] and set the wrench to the correct torque range. Begin tightening the bolts evenly, alternating between each bolt, to ensure the pressure is distributed evenly across the crankset.
6. Check the Tightness
After reaching the recommended torque value, check the tightness once more. If the torque wrench clicks or shows that the proper torque has been achieved, the bolts are tight enough. If the bolts are still not tight enough, repeat the process, ensuring to re-check the torque.
7. Final Inspection
Once the bolts are correctly torqued, double-check the crankset for any issues. Ensure that the crank arms are secure and there is no movement. Additionally, check the pedal threads to ensure there is no damage or cross-threading.
Troubleshooting Common Issues
1. Crank Arm Wobble
If you notice a wobble or play in the crank arm after tightening the bolts, the most common cause is insufficient torque. Recheck the torque and retighten the bolts if necessary.
2. Over-Tightening
If you accidentally over-tighten the bolts, you might notice damage to the crank arm or bottom bracket. Over-tightening can also result in stripped threads. In this case, you may need to replace the damaged parts.
3. Bolt Loosening Over Time
Crank arm bolts can loosen over time due to vibration and cycling stress. If you experience this issue, you may need to apply more grease to the threads or use thread-locking fluid designed for bike components.
Key Takeaways
- Torque Specs Matter: Always follow the recommended torque specifications (12-14 Nm for Shimano FC-5700) to avoid over-tightening or under-tightening.
- Use a Torque Wrench: A torque wrench is crucial for accurate tightening. It ensures you don’t risk damaging your bike or causing performance issues.
- Grease the Threads: Use a thin layer of grease to prevent corrosion and ensure smooth tightening.
Correctly tightening the crank arm bolts on your Shimano FC-5700 crankset is a straightforward process but requires precision. Following the steps outlined above will help you maintain optimal performance and avoid common issues like wobbling or power loss. Regular checks and maintenance will ensure your crankset stays in top condition for years of reliable riding.