BOO2 / BOO4 / RFC freecoaster maintenance


BOO2/BOO4 tools

  1. 2 x 23 mm wrench (if you don’t have a thin one just flex a normal one to the desired thickness)
  2. 2 mm hex wrench
  3. rubber hammer

Composition of the BOO 2 free coaster with numbered parts:

BOO2/BOO4 explosion

click image for special effect

  1. hex nut
  2. alloy end cap
  3. sealed cartridge bearing
  4. axle
  5. cartridge 1/8″ ball retainer
  6. clutch cone
  7. hub shell + fixed unit
  8. sealed cartridge bearing
  9. one piece driver
  10. sealed cartridge bearing
  11. alloy cone nut
  12. alloy flange nut

part 1: disassembling


remove the alloy flange nut (12), hex nut (1) and alloy cone nut (11)


rotate the driver (9) anticlockwise in order to remove it


take out the axle (4) with a rubber hammer


the inner life of the Boo2/Boo4 should come out of the freecoaster shell
(image with the new clutch version)


part 2: lubrication

Because the Boo2/Boo4 freecoaster contains only sealed bearings, there is almost no need to lubricate. But still, the sliding part of the clutch should be lubricated well for a better performance.
Lubricate it like it is shown in the pics below:


part 3: adjust coaster response

You can adjust the freecoaster response by changing the slide grade of the clutch on the axle. By loosening/tightening the allen screws on the clutch, the slide grade can be adjusted.
A high slide grade results in a long coaster response, a low slide grade results in a quicker coaster response. See pics and explanation below for further guidance.

By tightening the allen screws (with spring and ball inside), the slide grade will decrease (quick response), by loosening the allen screws, the slide grade will increase (slow response). Click the image above to see the clutch’s slide grade.

clutch slide grade/pedal clearance overview:
– high / ?  90 degrees
– average  / ~ 45 – 60 degrees
– low / ~ 10 – 30 degrees


part 4: assembling

Assemble the coaster step by step.


insert the axle/inner life carefully with the rubber hammer


grease the driver winding


insert the driver by rotating it clockwise


adjust axial play by tightening the hex nut with caution
tightening the hex nut too strongly may damage the bearings!
tighten the locknut to the hex nut

you’re done!!

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2 Responses to BOO2 / BOO4 / RFC freecoaster maintenance

  1. betsy abreu says:

    Waoo! This instructions really helped me out alot. I got a brand new boo4 and its making this grinding sounds and leaking grease from the driver side. Now I know how to take it apart and see what the problem is.

  2. Jason Harrison says:

    Thanks so much for this! It helped me feel a bit more comfortable with maintaining my hub. Great info!

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