Changing the bearings on a Brompton 2 speed wheel

Note: This guide is still a work in progress and will continue to be updated!

The Brompton C Line (and previous) two speed and single speed wheel are actually the same wheel (just with a different sprocket stack)

Wheel bearings:

This wheel has replaceable bearings in the hub:

6900-2RS in the non-drive side (we will replace with Enduro 6900 LLU)
6901-2RS in the drive side (we will replace with Enduro 6901 LLU)

And the following bearings in the freewheel body:

6900-2RS (we will replace with Enduro 6900 LLU)
6000-2RS (we will replace with Enduro 6000 LLU)

Note: the -2RS (e.g. in 6900-2RS) just means that both sides of the bearings are sealed with a rubber seal). The Enduro bearings have a better quality seal to help prevent / reduce dirt / water getting into the bearings and are designed for uses including hubs

Tools required:

You will need some tools:

• 17 mm cone wrench (e.g. Park Tool SCW-17)

Note: This is used on both sides of the wheel hub - both drive side and non-drive side

• Small flat head screwdriver (for removing the circlip which holds the sprocket stack in place)
• Circlip pliers (e.g. Draper Reversible Circlip Pliers for removing the circlip holding the free hub bearings in place) 
• Mallet (for tapping out the bearings)
• Bearing drifts / presses
• Vice - this may be required to help you remove the cone / locking nut
• Axle vice - this allows you to grip your axle using the vice without damaging it

Removal steps: (more detail shown below)

1. Remove the circlip holding the sprocket stack in place
2. Remove the sprocket stack
3. Undo the drive side lock nut and remove
4. Remove the circlip from the free hub body using circlip pliers
5. Remove the free hub body from the wheel
6. Tap out the bearings
7. Remove the spacer from the axle
8. Undo the non-drive side lock nut and remove
9. Remove the axle bearings!

Installation steps:

1. Install the spacer
2. Install the bearings into the free hub body
3. Install the circlip holding the bearings in place into the free hub body
4. Install the free hub onto the wheel
5. Tighten the drive side locknut 
6. Install the sprocket stack
7. Install the circlip holding the sprocket stack in place

Spacer:

step end on outside - towards driver

Last update: 12th May 2024