How to Install, Adjust, and Maintain the Zipp ZM 900 Hubs

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The Zipp ZM 900 hubs are a high-performance option for road and gravel riders, designed for durability and efficiency. Regular servicing ensures smooth operation and extends their lifespan. This guide provides detailed instructions on the installation, adjustment, and maintenance of the ZM 900 hubs.

Tools Required

Before beginning the installation or servicing process, gather the necessary tools.

  • Bearing press [paid link] tools (SRAM 6903, SRAM 63803, Zipp Bearing Press [paid link] Tool 23x32x7)
  • Blind hole bearing puller set
  • Axle and spindle vise inserts (Park Tool AV-4 or AV-5)
  • T-handle threaded bearing press [paid link]
  • Plastic or rubber mallet
  • Grease brush
  • Shop towels and isopropyl alcohol
  • Nitrile gloves and safety glasses
  • Zipp Cognition or Klüber Staburags NBU30 grease
  • SRAM Butter grease

Installing the ZM 900 Hubs

Proper installation of the ZM 900 hubs ensures optimal performance and longevity. Cleaning the surrounding area before installation prevents contamination and ensures smooth bearing operation.

Installing the Rear Hub

The rear hub installation process begins with inserting the axle through the non-drive side of the hub shell. Pressing the drive-side bearing into the hub shell using the SRAM 6903 bearing press tool ensures proper alignment. The non-drive-side bearing is then pressed into place using the SRAM 63803 tool, completing the bearing setup.

Applying SRAM Butter grease to the ratchet ring is essential for smooth engagement. The freehub body is installed by twisting it counterclockwise, ensuring a secure fit. Finally, pressing the end caps onto the axle completes the installation.

Installing the Front Hub

The front hub follows a similar process. The axle is inserted through the non-drive side of the hub shell, followed by pressing the non-drive-side bearing into place using the Zipp Bearing Press Tool 23x32x7. The axle is then passed through the bearing, and the drive-side bearing is pressed into the shell. Before installing the end caps, the axle ends and bearing contact points must be lubricated to prevent friction.

Proper hub installation ensures that the wheels roll smoothly with minimal resistance. After installation, checking for any unusual movement or noise will help confirm that the hub is properly seated.

Adjusting the ZM 900 Hubs

The ZM 900 hubs are designed for minimal adjustment, but factors such as bearing wear and contamination can lead to unwanted play or friction.

Checking for Play in the Bearings

A well-installed hub should spin freely without excessive movement. If lateral play is detected while holding the wheel by the rim, the hub may need adjustment.

Tightening the End Caps

Firmly pressing the end caps onto the axle ensures that any gaps are eliminated. If excessive play remains, it may indicate worn bearings that require replacement.

Lubricating the Freehub Body

Smooth engagement is essential for proper hub function. If the freehub mechanism starts feeling rough or sticky, it should be cleaned and relubricated. The freehub body is removed and cleaned thoroughly, and SRAM Butter grease is applied to the pawls and leaf springs before reinstallation.

When servicing other drivetrain components, such as chains, proper lubrication and maintenance ensure compatibility with the hubs. Check out the guide on How to Clean Your Bike Chain for best practices.

Maintaining the ZM 900 Hubs

Routine maintenance ensures that the ZM 900 hubs operate smoothly and last longer. Over time, dirt, moisture, and regular use can impact performance, making regular cleaning and bearing servicing essential.

Cleaning the Hub Shell

Dirt buildup can cause premature wear on the bearings. Cleaning the hub exterior with isopropyl alcohol and a lint-free shop towel prevents contaminants from reaching internal components. Harsh chemicals like acetone should be avoided, as they may damage the hub’s surface.

Servicing the Bearings

Bearings are critical for smooth rotation, and over time, they may wear out and require replacement.

Rear Hub Bearing Replacement

Bearing replacement begins by removing the end caps with a vise and pulling up on the wheel. The drive-side bearing is dislodged by tapping the axle with a plastic mallet, and new bearings are pressed into place using the appropriate bearing press tools.

For detailed chain replacement tips, refer to How to Replace Your Bike Chain to maintain drivetrain efficiency.

Front Hub Bearing Replacement

The non-drive-side end cap is removed using a vise, followed by gently tapping the axle with a mallet to dislodge the bearing. The new bearings are then pressed into the hub shell using the Zipp Bearing Press Tool 23x32x7, ensuring that they are seated correctly.

Maintaining the Freehub

Regular cleaning and lubrication of the freehub mechanism ensure consistent engagement. The pawls and leaf springs should be removed, cleaned with isopropyl alcohol, and reassembled with fresh SRAM Butter grease.

If gear shifting issues arise due to freehub wear, refer to Troubleshooting Common Gear Shifting Problems on Your Road Bike for solutions.