Threaded Headset Removal and Replacement

Note: Headsets contain a number of moving parts that stack together in a particular order. When removing the headset, be sure to organize the parts in the order in which you removed them, so that you can reinstall them in the same order.

The headset shown below has sealed cartridge bearings, but is otherwise similar to other headsets.

Most headsets have loose ball bearings, or ball bearings in retainer cages.

Fig. 1

Headset Removal

1. Remove the stem

Fig. 2

Fig. 3a

Loosen stem expander bolt using a 5mm or 6mm hex wrench, or 13mm or 14mm box wrench (when appropriate). Turn the bolt counterclockwise four or five full turns.

Do not completely loosen bolt! (The internal expander wedge/nut will detach from bolt, making stem extraction more difficult.)

Example stem, expander bolt and expander wedge shown below.

Fig. 3b

Using a hammer, tap the stem expander bolt straight down. It may take a few firm blows with the hammer to loosen the expander wedge/nut from the stem.

NOTE: If the stem expander bolt is recessed in the top of the stem (as shown in Fig. 2), it may be necessary to tap the top of the hex wrench to loosen the stem. Be careful not to damage the tool.

Fig. 4

Once the stem is loose, slide the stem up and out of the steerer tube.

The front brake cable may have to be disconnected to allow stem to rise out of fork steerer tube.

Attach the stem/handlebars to the frame using shop towels and toe straps or other ties.

2. Headset and Fork Removal

Fig. 5

Loosen and remove the locknut, turning counterclockwise with the appropriate headset wrench while holding the adjustable cup with another headset wrench.

NOTE: If the adjustable cup does not have wrench flats, you can hold onto the wheel for leverage. If you have already removed the wheel, you can wedge a piece of wood between the fork blades for leverage.

Fig. 6

Remove any spacers or washers.

Remove the front wheel before loosening the adjustable cup.

Fig. 7

While holding onto the fork with one hand, unscrew (counterclockwise) and remove the adjustable cup either by hand or with a wrench.

Fig.8

Use a magnet to pick up the bearings if they do not have a retainer ring.

Fig.9

Disconnect front brake cable from brake pinch bolt. (See Brake Assembly Tutorial, add link)

Remove the fork, picking up the lower set of bearings with a magnet if they are loose, and set aside.

3. Inspect headset for wear

Fig. 10

Wipe all bearing surfaces clean, if necessary using a solvent to remove dirt and grease. If you use solvent, be sure to clean and dry the parts before reinstalling.

Use compressed air to blow grease and solvent out of the bearing retainer rings.

Once the parts are clean, inspect for damage and wear.

Fig.11

The wear on the bearing surfaces should be even, not pitted.

Fig.12

Look for dents/marks on the bearing surfaces, if the bearings have made dents in the cups/cones, they may need replacement.

To check for cuts/gouges, run a soft metal pointed tool along each bearing surface and feel for cuts.

4. Remove crown race

Before removing the crown race, it may be necessary to remove the brake caliper. If the brake caliper attaches at the fork crown, it will need to be removed.

(See Brake Caliper Removal Instructions)

Fig. 13

Place the crown race removal tool over the fork crown, contacting the underside of the fork crown race.

Flip the fork upside down, either hold the fork blade wth one hand as shown below, or rest the top of the steerer tube on a block of wood on the floor or bench.

Fig.14

Tap the top of the crown race remover repeatedly with a hammer until the crown race comes loose and falls off.

NOTE: If the crown race removal tool shown does not fit over the fork crown, it may be necessary to use a different crown race remover. Shown below: Park Universal Crown Race Puller, Courtesy of Park Tools USA.

Fig. 15

5. Remove upper bearing race

Fig. 16

Use an appropriate Headset Cup Remover tool.

Shown here is a Park Tools USA RT-1.

Fig. 17

Insert the solid end of the tool into the top of the head tube.

Fig. 18

Slide the tool into the head tube until the slotted end goes into the head tube, and the flanges press out against the head tube past the headset cup. Fig. 19

Fig. 20

Holding the upper headset cup, strike the solid end of the removal tool with a hammer until the headset cup pops out of the head tube. Fig. 21

6. Remove lower bearing race

Fig. 22

Insert the solid end of the universal head cup removal tool into the bottom of the head tube.

Fig. 23

Slide the tool into the head tube until the slotted end goes into the head tube, and the flanges press out against the head tube past the lower headset cup.

Fig. 24

Holding the lower bearing race, strike the solid end of the removal tool with a hammer until the head cup pops out of the head tube. Fig. 25

Installation of New Headset

7a. Measure fork crown and race diameter

These instructions for installing a new headset assume that the new headset's stack height is equivalent to the old one.

It is okay if the new headset's stack height is less than the old one, but it is not okay for it to be much larger.

If the new headset has a larger stack height, the steerer tube may end up being too short for the headset.

The following measurement procedures are to ensure that the headset is compatible with the fork and the head tube.

Fig. 26

Using a vernier or dial caliper, measure the outside diameter of the crown race seat on the fork. Record the measurement.

Fig. 27

Measure the inside diameter of the fork crown race using the caliper and record that measurement.

Compare the two measurements. The inside diameter of the crown race should be 0.1mm smaller than the outside diameter of the crown race seat on the fork. This is an intentional interference fit.

7b. Measure headset cup and head tube diameter.

Fig. 28

Using the caliper, measure the outside diameter of the headset cup flanges.

Measure the inside diameter of the head tube.

The headset cup flanges should be .2mm larger than the inside of the head tube. This is an intentional interference fit. Fig. 29

8. Install the crown race

Fig. 30

Lightly grease the crown race seat on the fork.

Slide the crown race onto the steerer tube, with the flat side against the fork crown. Fig. 31

Fig. 32

Fig. 34

Select the crown race setting tool insert that matches your crown race. The edge of the tool should fit on either the inside or outside edge of the crown race, but not on the middle of the bearing surface. Shown at left: Park Tools USA CRS-1 Crown Race Setting System.
Fig. 33

Fig. 35

Slide the crown race setting tool over the steerer tube.

Fig. 36

Hold the fork and the crown race setting tool upright in the air.

Lightly tap the top of the crown race setting tool with a hammer.

Examine alignment of the crown race, if starting to become misaligned, extract it and start over.

Once good alignment is achieved, continue tapping until the crown race is completely seated on the fork crown.

A good indication of full seating is grease squeezed out under the crown race evenly.

Fig. 37

Fig. 38

9. Install the lower bearing race

Fig. 39

Fig. 40

Use an appropriate headset press.

Shown here is a Park Tools USA HHP-1.

Identify the fitting that matches the inside of your headset cups.

Fig. 41

Grease the flange on the lower headset cup.

Fig. 42

Fig. 43

Fig. 44

Use the headset press to install the lower headset cup in the headtube, making sure that it seats flush against the head tube. Note the quick release that allows you to remove and replace the bottom fitting on the headset press.

Turn the handles of the press clockwise to press the headset cup into the head tube.

Fig. 45

Fig. 46

10. Repeat step 9 with upper headset cup.

11. Install fork

Fig. 47

Fig. 48

For loose bearing headsets, smear a thick bed of grease on the bearing surface of the lower cup, and stick the bearings in the grease. Slide the steerer tube through the head tub and snug against the bearings. NOTE: The headset shown in the picture has sealed cartridge bearings. These only require a thin coat of grease.

Fig. 49

For loose bearing headsets, smear a thick bed of grease on the bearing surface of the upper cup, and set the bearings in the grease.

Shown here is a sealed cartridge bearing headset, so only very thin amount of grease is needed.

Fig. 50

Grease the threads of the steerer tube.

Thread the adjustable cup onto the steerer tube clockwise until it just contacts the bearings.

Don't tighten it down on the bearings.

12. Ensure appropriate steerer tube thread protrusion

When installing a headset, it is important that the locknut engages at least 5mm of threads on the steerer tube, without bottoming out on the steerer tube before it gets tight.

If the locknut has insufficient thread engagement, it can damage the threads.

If the locknut bottoms out before it tightens the headset, then the headset adjustment will come loose.

The following procedure will ensure that neither of these things happens.

Fig. 51

Fig. 52

Slide any washers, spacers and cable hangers over the steerer tube.

One or more of the washers should have a tab on the inside. Be sure to align this tab with the groove on the steerer tube.

Fig. 53

Fig. 54

Fig. 55

Once the washers have been installed, measure the amount of visible threads with a caliper. There needs to be at least 5mm of threads above the last spacer.

Fig. 56

Fig. 57

Using the caliper, measure the distance from the bottom edge of the locknut, to the top flange.

This distance must be greater than the amount of threads showing above the spacers on the steerer tube.

If the amount of visible threads on the steerer tube is less than 5mm, you will need to replace the washers with thinner ones until you get 5mm of visible threads.

If the amount of visible threads is greater than the depth of the locknut as measured above, then you will need to add washers.

13. Headset Adjustment

The optimum headset adjustment should allow rotation of the headset to be as smooth as possible without any play.

In the case of used components, it is higher priority to have no play rather than smoothness.

A loose headset will wear out very quickly, as the bearings rock back and forth, denting the bearing races.

Fig. 58

Thread the locknut onto the steerer tube clockwise.

By hand, adjust the adjustable cup until there is only a tiny amount of play, but it still turns smoothly.

Fig. 59

Gradually tighten the locknut with the appropriate headset or adjustable wrench while holding the adjustable cup with a thin headset wrench.

As you gradually tighten the locknut, check for play and smooth spinning of the fork to avoid over-tightening.

Be aware that tightening the locknut will tighten your headset adjustment somewhat, getting rid of the play that you started with.

Check your adjustment by trying to rock the fork and headset back and forth, feeling for play.

Also spin the headset slowely by hand, feeling for rough or tight spots.

If necessary you can install the front wheel and hold onto it for leverage while tightening the locknut.

By the time you are done adjusting the headset, the locknut should be tightened to 25 ft-lb of torque. (If necessary, see section about torque values)

Remember that tightening the locknut will affect the headset adjustment.

If the adjustment is not smooth and free of play, make adjustments to the headset by loosening the locknut and turning the adjustable cup to loosen or tighten the adjustment.

Tighten the locknut and recheck the adjustment.

14. Install Front Wheel

Install the front wheel in the fork. (see front wheel installation if necessary)

15. Install Stem

Fig. 60

Fig. 61

Grease the stem, expander bolt and expander wedge, and slide the stem into the steerer tube.

Fig. 62

Set the stem at the desired height, making sure that it is below the maximum height line.

Line the stem up with the front wheel and tighten the stem bolt with the appropriate wrench to 12-21 ft-lb of torque. (See explanation of torque values if necessary)

Make sure the stem is secure by holding the front wheel and trying to turn the handle bar. If the bar turns, the stem is not tight enough, and needs to be repositioned and tightened.

16. Install Front Brake

Reinstall the front brake, if it was removed. (If necessary, see instructions for front brake installation)

17. Check Headset Adjustment

Place the bike on the ground, and while squeezing the front brake lever, try to rock the front wheel back and forth on the ground.

Feel for play in the headset, and adjust if necessary.