The Shimano FH-6800 [paid link] hub is a well-regarded option for road cyclists, offering smooth engagement and durability. However, like all components, the bearings inside your FH-6800 [paid link] hub may wear over time. Properly servicing or replacing these bearings is essential for maintaining optimal performance, preventing damage, and ensuring longevity. In this article, we’ll guide you through the steps to replace or service the bearings in your Shimano FH-6800 [paid link] hub.

Understanding the Importance of Bearings in Your FH-6800 Hub

Bearings play a critical role in the performance of your Shimano FH-6800 hub. They help reduce friction, which allows the wheel to rotate smoothly and efficiently. As the bearings age, they can become damaged or worn out, leading to issues such as rough spinning, resistance, or even hub failure. Regular maintenance and timely bearing replacement are essential to keep your bike running smoothly.

Common Signs That Bearings Need Attention:

• Rough or stiff hub rotation: If you notice that your wheel spins unevenly or with resistance, it could be a sign of worn bearings.
• Noise from the hub: Unusual grinding or clicking sounds may indicate that the bearings are starting to degrade.
• Excessive play in the hub: If there is noticeable movement or wobble in the hub, it could mean the bearings are no longer functioning correctly.

Tools Required

To replace or service the bearings in your Shimano FH-6800 hub, you will need the following tools:

• Hub tool [paid link] (compatible with Shimano FH-6800)
• 8mm and 10mm hex wrenches
• Bearing press [paid link] tool (or a hammer and drift punch)
• Clean rags or paper towels
• Grease (high-quality bicycle bearing grease)
• Small screwdriver (for removing the freehub body)
• Cotter pin or snap ring tool
• Plastic mallet (optional, for tapping parts without damaging them)

Disassembling the Shimano FH-6800 Hub

Before you can replace or service the bearings, you must disassemble the FH-6800 hub. This process requires careful attention to avoid damaging components that are critical for reassembly.

1. Remove the Rear Wheel

Start by removing the rear wheel from the bike. Make sure the bike is in a secure stand or resting on its side while you work.

2. Remove the Freehub Body

To access the hub bearings, you need to remove the freehub body. Use a 10mm hex wrench to remove the freehub body by unscrewing the lockring. Once the lockring is removed, gently pull off the freehub body. You may need to use a small screwdriver or a similar tool to carefully pry it off, depending on how tight it is.

3. Remove the Hub Axle

Next, use an 8mm hex wrench to remove the axle from the hub. This will require you to remove any end caps and ensure that all axle components come off smoothly.

4. Extract the Bearings

Once the axle is removed, you’ll see the bearings housed within the hub shell. These bearings may be held in place by a snap ring or a retaining collar. Use a cotter pin tool or snap ring pliers to remove the retaining ring. Carefully pull the bearings out of the hub. If the bearings are stuck, you may need to use a bearing press [paid link] or gently tap the hub with a plastic mallet to free them.

Inspecting and Replacing the Bearings

1. Inspect the Bearings

After removing the bearings, inspect them for signs of wear. Look for any discoloration, pitting, or rough spots that could cause friction when the hub is reassembled. If the bearings feel rough or gritty when turned by hand, they are likely damaged and should be replaced.

2. Choose the Correct Bearings

Ensure that you replace the bearings with Shimano-approved replacement parts. The FH-6800 hub typically uses sealed cartridge bearings, which are widely available at bike shops or through Shimano distributors. Using non-compatible bearings may result in poor performance or premature wear.

3. Installing New Bearings

Before installing the new bearings, clean the hub shell thoroughly to remove any dirt or old grease. Apply a thin layer of high-quality grease to the bearing seats in the hub shell to ensure smooth operation and prevent corrosion.

Carefully press the new bearings into place using a bearing press [paid link] tool or a suitable drift punch. Make sure the bearings sit flush in the hub shell and are properly aligned.

Reassembling the Shimano FH-6800 Hub

1. Reinstall the Hub Axle

Once the new bearings are in place, reinsert the hub axle. Tighten it securely, ensuring that all washers and spacers are in their correct positions.

2. Reattach the Freehub Body

Next, reinstall the freehub body by sliding it back onto the hub axle. Secure it with the lockring, using the 10mm hex wrench to tighten it. Be careful not to overtighten, as this could damage the threads.

3. Check for Smooth Rotation

Before reinstalling the wheel, check that the hub spins smoothly by turning the axle by hand. There should be no grinding, resistance, or play in the bearings. If the hub feels rough or loose, you may need to adjust the bearing preload or check that the bearings were installed correctly.

4. Reinstall the Rear Wheel

With the hub reassembled, reinstall the rear wheel onto the bike, ensuring that the axle is securely tightened in the dropouts.

Conclusion

Replacing or servicing the bearings in your Shimano FH-6800 hub is an essential maintenance task to keep your bike performing at its best. By following these steps, you can replace worn bearings and restore smooth, efficient operation to your hub. Regular maintenance will not only enhance your riding experience but also prolong the lifespan of your hub, ensuring that your bike stays in top condition for many miles to come. Always use high-quality replacement parts and proper tools to ensure the best results.