How to Replace or Service the Bearings in Your Shimano FH-5800 Hub

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The Shimano FH-5800 [paid link] hub is a popular choice among road cyclists due to its reliability and smooth performance. However, like all bike components, it requires proper maintenance to keep it performing at its best. One of the most crucial aspects of maintaining this hub is ensuring the bearings are in good condition. Over time, bearings in the FH-5800 [paid link] hub can wear out, leading to poor performance and potential damage to other components. This guide will walk you through the process of replacing or servicing the bearings in your Shimano FH-5800 [paid link] hub, ensuring that your bike continues to run smoothly.

Tools Required

Before beginning the bearing replacement or service, ensure you have the following tools at your disposal:

  • 15mm wrench (for wheel removal)
  • Hub cone wrench [paid link]
  • Socket wrench with the correct socket for the axle
  • 5mm Allen wrench [paid link]
  • Bearing puller (optional)
  • Replacement bearings (specifically for the Shimano FH-5800 hub)
  • Grease (preferably a waterproof, high-quality bike grease)
  • Clean rags or paper towels
  • Isopropyl alcohol (for cleaning)
  • A small brush (for cleaning the hub)

Removing the Hub from the Wheel

Before you can replace or service the bearings, you need to remove the FH-5800 hub from the wheel.

  1. Remove the Wheel: Use a 15mm wrench to loosen the quick-release or thru-axle, depending on your setup. Once the axle is loose, carefully remove the wheel from the bike frame.
  2. Disassemble the Hub: Use a 5mm Allen wrench [paid link] to remove the freehub body from the FH-5800 hub. If the freehub is stubborn, use a socket wrench to remove any bolts securing it.
  3. Inspect the Hub Shell: After removing the freehub body, carefully inspect the hub shell to ensure that no dirt or debris has entered the hub.

Accessing the Bearings

Once you’ve removed the hub from the wheel and disassembled the necessary parts, you can access the bearings.

  1. Locate the Bearings: The Shimano FH-5800 hub typically has two sets of ball bearings – one on each side of the hub shell. You’ll need to remove the cone and lock nut to access these bearings.
  2. Remove the Cone and Lock Nut: Use the hub cone wrench [paid link] to loosen and remove the lock nuts and cones. The cones are the small, conical pieces that apply pressure to the bearings to ensure they stay in place.
  3. Remove the Bearings: Gently remove the bearings from their seats using a small brush or bearing puller. If the bearings are stuck or difficult to remove, be careful not to damage the bearing seats inside the hub.

Cleaning the Hub

Before installing new bearings or servicing the existing ones, thoroughly clean the hub shell and other components.

  1. Clean the Hub Shell: Use a clean rag or paper towel to wipe away dirt and grime from the inside of the hub shell. Isopropyl alcohol is effective for removing stubborn grease and grime.
  2. Clean the Bearings (If Servicing): If you are servicing the existing bearings rather than replacing them, clean them with a brush and alcohol to remove old grease, dirt, and any corrosion. Inspect the bearings for signs of wear, pitting, or damage. If they feel rough or gritty, they should be replaced.

Installing New Bearings or Servicing Existing Ones

Now that the bearings are exposed and the hub is clean, you can either install new bearings or service the old ones.

Replacing the Bearings

  1. Apply Grease: Before installing the new bearings, apply a small amount of bike-specific grease to the bearing seats inside the hub shell. This helps the bearings seat properly and reduces friction.
  2. Install the New Bearings: Place the new bearings into their respective positions inside the hub shell. Use your fingers or a small tool to carefully position them without damaging the bearing races.
  3. Reassemble the Hub: Once the new bearings are in place, reinstall the cones and lock nuts. Tighten them securely but not too much, as over-tightening can cause premature bearing wear.
  4. Lubricate the Freehub Body: If you removed the freehub body, ensure it is properly lubricated before reattaching it to the hub shell. Apply grease to the freehub body’s internal mechanisms and reassemble it onto the hub.

Servicing the Existing Bearings

  1. Clean and Inspect the Bearings: If the bearings are still in good condition but need maintenance, clean them with alcohol and inspect each ball for smoothness. If they move freely without any rough spots, they can be reused.
  2. Grease the Bearings: Apply a thin layer of fresh grease to the bearings. Make sure that the grease coats all the ball bearings and that there is no excess grease, which could attract dirt.
  3. Reinstall the Bearings: Place the serviced bearings back into their respective positions and reassemble the hub as described above.

Reassembling the Hub

After replacing or servicing the bearings, it’s time to reassemble the entire hub.

  1. Reinstall the Lock Nuts and Cones: Tighten the cones back into place with the cone wrench [paid link]. Be sure not to overtighten, as this could cause the bearings to wear prematurely. The cones should be tight enough to apply pressure to the bearings without creating excessive friction.
  2. Check for Smoothness: Once everything is reassembled, check the hub for smoothness. Spin the hub by hand and feel for any rough spots or stiffness. The hub should rotate freely with minimal resistance.
  3. Reattach the Freehub: After ensuring the bearings are properly installed and adjusted, reinstall the freehub body. Secure it into place, making sure it rotates smoothly.

Final Adjustments and Testing

Once the bearing replacement or service is complete, it’s essential to perform final adjustments and test the hub before riding.

  1. Test the Hub on the Bike: Reinstall the wheel onto the bike and tighten the axle securely. Spin the wheel to check for smooth rolling and ensure that the hub is functioning correctly. If there is any play or roughness, you may need to re-adjust the cones or bearings.
  2. Check for Noise: Pay attention to any unusual noise from the hub, which could indicate improper bearing installation or adjustment. A quiet, smooth ride is the goal.
  3. Ensure Proper Freehub Engagement: Confirm that the freehub body engages properly when coasting and disengages smoothly when pedaling. Any issues here could indicate problems with the freehub mechanism itself, not just the bearings.

Conclusion

Replacing or servicing the bearings in your Shimano FH-5800 hub is a crucial task for maintaining the longevity and performance of your wheelset. By following these steps carefully, you can ensure that your hub continues to roll smoothly and efficiently for many rides to come. Regular maintenance and timely bearing replacement can save you from more costly repairs and improve your overall cycling experience.