How to Replace or Service the Bearings in Your Shimano FH-6800 Hub

Posted on
in No category

The Shimano FH-6800 [paid link] hub is a popular choice among road cyclists due to its reliability, smooth performance, and solid construction. Over time, however, like all components, the bearings in the hub can wear down, causing performance issues like roughness, noise, or poor engagement. Replacing or servicing the bearings can restore your hub to peak performance. This guide provides a step-by-step approach to help you replace or service the bearings in your Shimano FH-6800 [paid link] hub.

Tools Required:

  • 10mm socket wrench or adjustable spanner
  • 5mm Allen wrench [paid link]
  • 3mm Allen wrench [paid link]
  • Bearing press [paid link] (optional)
  • Grease (high-quality bicycle bearing grease)
  • Rags for cleaning
  • Screwdrivers (flathead)
  • Hammer (if needed)
  • Replacement bearings (if necessary)
  • Lubricant (for the freehub body)

Disassembling the Shimano FH-6800 Hub

Before replacing or servicing the bearings, the first step is to properly disassemble the hub.

  1. Remove the wheel: Start by removing the rear wheel from your bike, ensuring it’s placed on a stable surface.
  2. Remove the freehub body: Use a 10mm socket wrench or an adjustable spanner to unscrew the locknut on the non-drive side. After loosening the nut, slide the freehub body off the hub shell.
  3. Remove the axle and bearings: With the freehub body removed, you will expose the bearings inside the hub shell. Use a 5mm Allen wrench [paid link] to unscrew the axle. Once the axle is removed, carefully remove the bearings and any other internal parts.

Inspecting the Bearings

Once the bearings are exposed, it’s essential to inspect them for wear and damage.

  • Visual inspection: Examine the bearings closely. Look for any signs of rust, pitting, or discoloration. If you notice any of these signs, it is a clear indicator that the bearings need to be replaced.
  • Spin test: Gently spin each bearing to feel for any roughness or resistance. If the bearings do not spin smoothly or feel gritty, they should be replaced.

If the bearings appear to be in good condition and only require servicing, proceed to the cleaning and lubrication steps. If they are worn or damaged, proceed to the bearing replacement steps.

Servicing the Bearings

If your bearings are in good condition and only need cleaning and lubrication, follow these steps:

  1. Clean the bearings: Use a rag to wipe away any dirt or grime from the bearings and their seat. For a more thorough cleaning, you can use a degreaser, but make sure to dry the parts completely afterward.
  2. Lubricate the bearings: Apply a thin layer of high-quality bicycle bearing grease to the bearings. Be sure to coat all the moving surfaces to ensure smooth operation and to prevent future wear.
  3. Reassemble the hub: After lubrication, carefully place the bearings back into their seats. Reinsert the axle and reassemble the freehub body and hub shell. Ensure everything is seated properly before reattaching the locknut on the non-drive side.

Replacing the Bearings

If the bearings need to be replaced, follow these steps:

  1. Remove the old bearings: Using a flathead screwdriver or bearing puller, carefully pry out the old bearings from the hub shell. Take care not to damage the bearing seats.
  2. Install new bearings: Take your replacement bearings and carefully place them into the bearing seats. If the bearings are a press-fit design, use a bearing press [paid link] to insert them evenly and securely. Ensure the bearings are aligned properly to avoid any misalignment.
  3. Reassemble the hub: Once the new bearings are installed, apply a thin coat of grease to the bearings and reassemble the hub as described in the servicing section.

Adjusting the Freehub Body and Axle

After replacing or servicing the bearings, it is important to ensure the freehub body and axle are correctly adjusted to prevent issues such as excessive drag or play.

  1. Lubricate the freehub body: Before reattaching the freehub body to the hub, apply a light coating of lubricant to the inside of the freehub body and the ratchet mechanism. This will improve engagement and smoothness.
  2. Reassemble the axle: Slide the axle back through the hub shell and tighten it securely with the 5mm Allen wrench. Check for any play by rotating the axle; there should be minimal movement.
  3. Reinstall the locknut: After the axle is properly adjusted, screw the locknut back into place on the non-drive side, tightening it securely with the 10mm socket wrench.

Final Checks

After the hub has been reassembled, perform the following checks to ensure it is functioning properly:

  • Spin test: Rotate the hub by hand to check for smoothness. The hub should spin freely without any resistance or roughness.
  • Engagement test: Engage and disengage the freehub by turning the wheel in both directions. Ensure that the ratchet mechanism is functioning smoothly and there is no skipping or hesitation.
  • Wheel reinstallation: Reinstall the wheel back on the bike and make sure the hub is securely attached to the dropouts.

Troubleshooting Common Issues

Even after replacing or servicing the bearings, some common issues may arise. Here are a few things to check if you notice any problems:

  • Noisy hub: If your hub is making noise after servicing or replacing the bearings, it could be due to improper lubrication or incorrect bearing seating. Double-check the bearings for proper installation and ensure they are well-lubricated.
  • Rough rotation: If the hub feels rough even after bearing replacement, the bearings may not have been seated correctly or may require additional lubrication. Recheck the bearing installation and ensure everything is tight.
  • Play in the axle: If you notice play in the axle, it could be due to improper tightening of the axle or locknut. Make sure all components are securely tightened and properly aligned.

Conclusion

Servicing or replacing the bearings in your Shimano FH-6800 [paid link] hub is a great way to restore smooth performance and extend the lifespan of your hub. By following the steps outlined in this guide, you can ensure that your hub continues to provide reliable, smooth performance for many miles of cycling. Always inspect the bearings regularly for signs of wear and keep your hub clean and lubricated for optimal performance. If you are unsure about any step in the process or encounter any issues, it may be best to consult a professional mechanic for further assistance.