| This
information is intended for the mechanic who already possesses
a familiarity with headset installation technique
and who is interested in both the finer points of proper headset
setup and trouble shooting for best headset performance.
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Frame Preparation:
Head tube preparation is one of the most important and most
often overlooked elements in headset setup and performance.
Especially with high end frames, it is often assumed that
if a frame is new or already has a headset installed that
the frame must have been properly prepared at the factory.
This is very often not the case. We recommend a careful inspection
of the facing and reaming of the head tube before installation.
Ream and face the head tube as necessary to ensure that the
head tube is faced square and bored to the proper dimensions
(see chart below).
Using a small file or sand paper, carefully remove any sharp
edges or burrs and slightly round the inside edges of the
head tube at the top and bottom to prevent shearing any metal
from the cups during installation.
Clean to remove any chips, shavings, and/or cutting oil.
The proper press fit should be with no more than .1mm (.004")
of interference. See chart below for correct head tube bore
size. Do not file or otherwise remove material from the cups
to make them fit.
Facing Tolerance:
The recommended tolerances for parallelness of the end faces
of the head tube is not to exceed .075mm (.003"). Because
facing tolerance is actually more complicated than just having
the faces parallel, there is really no accurate way for the
average bike shop to measure it. We recommend inking the faces
of the head tube with a marker and using the facing tool to
see that it removes the ink evenly and completely all the
way around. Be sure to use the center guide in the opposing
bore to assure alignment. Cut metal as necessary until all
of the ink is removed.
Bore Sizing:
Head Tube Bore Size
1" Standard 30.1mm
1" BMX 32.7mm
1-1/8" 33.9mm
1-1/4" 36.9mm
Most reamers are .2mm under the nominal cup size while we
recommend that the head tube bore be cut to .1mm under. The
use of these reamers will produce varying finished bore sizes
depending on the properties of the material being cut, and
how much reaming is performed. With many materials you may
net the correct bore size, however, on materials such as titanium
or hard aluminum, the reamer may cut a clean bore in its exact
size or smaller. On the other hand, if you face a lot of material
with the reamer in the bore, the reamed bore may become oversized.
Because the equipment necessary to determine exact bore sizes
is not commonly found in most bicycle shops, attentively pressing
the cups is the most practical test. It shouldnít be
necessary to ìreef" on the press. An exceedingly
difficult cup press is an indication that the head tube bore
is undersized. If the bore is still undersized after reaming,
it may be necessary to use another method to achieve the proper
size. One trick we have used is to first press cheap steel
headset cups to smooth and stretch the bore slightly. Then,
remove and press our cups.
**Note**
The SteelSet headset uses a 1" deep cup skirt that will
require a deeper bore than a conventional frame will have.
The depth of the bore must exceed the depth of the skirt by
a minimum of .25" (~7mm) for a total depth of 1.25"
(~32mm) in order to get a cup removal tool behind the cup
skirt. Even then, the geometry of the inside of the head tube
may make SteelSet removal impossible and some frames are simply
not compatible with the SteelSet. Reaming your head tube bore
deeper than its stock condition may void your frame warranty
and could critically weaken your frame. Check with your frame
manufacturer before installing a SteelSet in your bike or
reaming your head tube bore any deeper than they did at the
frame factory.
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Additional
Edge Preparation:
Another aspect of preparation that is often overlooked is
the chamfer on the inside of the head tube bore (top and bottom)
and the removal of any sharp edges or burrs. We recommend
a chamfer width of .25mm (.010"). A clean chamfer allows
the cup to be pressed without shaving metal and to sit flat
against the tube face without cutting into the small radius
in the corner of the cup skirt. A cut in this area of the
cup may cause cracks to form over time.
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Pressing
Cups:
For proper installation of the cups, the press fit sizing
and facing should be within our recommendations (See Frame
Preparation, Facing Tolerance, and Bore Sizing above). After
reaming and facing or verification of tolerances, test fit
cups by attempting to insert them into frame by hand. This
test will only indicate an oversize bore condition but is
very important. The cup should only begin to fit into the
bore less than a millimeter. If the cup can be inserted by
hand more than 1/3 the total distance, the bore is too big
for a proper fit. This loose fit may result in movement of
the cup in the frame possibly causing creaking noises and
stretching of the headtube. Oversize cups are available in
incremented sized to establish proper fit into frame.
NOTE: We do not recommend using Loc-Tite and/or similar products
to make up for a loose fit as the load forces tend to exceed
their holding power causing them to disintegrate and allow
movement. While they may seem to work at first, they will
usually fail in less than a year. We recommend using our headset
installation adapters on the headset press. These adapters
help ensure that pressure is applied evenly across the top
of the cup and not on the bearing and that the cups press
straight into the frame without damage from the tool.
For proper alignment and fit, both cups must be inserted
parallel and square to the head tube. Press in both bearing
cups using a headset installation press fitted with our press
tool adapters.
Note: We do not recommend for or against the application
of grease, antisieze, or Loc Tite while pressing in cups with
a proper fit – we leave this choise to the discretion
of the mechanic installing the headset.
Once the cups are pressed in, they should be seated flatly
against the head tube. If they do not sit flat, the chamfer
on the head tube bore may be inadequate or the head tube bore
may not be parallel to the head tube axis.
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Fork Preparation:
Reaming and facing of the fork may be necessary,
but is not critical unless it is grossly out of parallel or
oversize. The crown race face and seat should be square and
parallel to the steerer tube and its outer diameter should
not exceed .1mm larger than the inner diameter of the base
plate. Most available reamers/facers are adequate for these
tolerances. Clean to remove any chips, shavings, and/or cutting
oil. The proper press fit should be with no more than .1mm
(.004") of interference. See chart below for correct
crown race seat size.
Base Plate Seat O.D. 1" Standard 26.5mm
1" BMX 26.5mm
1-1/8" 30.1mm
1-1/4" 33.1mm
Note: Do not attempt to install a baseplate that does not
press properly. Centerpunching, knurling, and/or the application
of LocTite or similar products is not recommended as the load
forces will exceed the holding power of any of these treatments
and eventually allow the baseplate to move. This movement
will seemingly create a loose headset effect. Baseplates with
undersized bores are available in incremented sizes for proper
fit.
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Installation of
Base Plate:
Slide the base plate, conical side up,
onto the steerer tube. With the beveled side of the base plate
installation adapter against the base plate, use a crown race
setting tool to set the base plate. The base plate installation
adapter helps to protect the conical bearing contact surface
on the base plate from damage due to the crown race installation
tool.
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Additional Installation
Notes for Threadless Systems:
NOTHREADSET™
Cut Steerer tube and Install Star Nut:
Insert fork into frame.
Remove o-ring from bearing cap and slide bearing cap, then
any spacers and the stem over steerer tube. Scribe a line
flush with top of stem.
Remove stem and mark another line 3mm below the first. Cut
on the lower line with a hacksaw. When sizing the steerer
tube it is important to make sure it extends into the stem
as far as possible without colliding with the stem cap. In
fact the steerer tube may extend through the stem as long
as adequate spacers are placed between the stem and stem cap.
This method has been very popular and effective in BMX installations.
Remove all sharp edges from inside and outside of steerer
tube. With sandpaper, round outside edge of tube to avoid
shearing the o-ring upon installation.
Thread star nut onto installation tool. If installation tool
is not available, thread bolt well into star nut and use it
to drive the star nut 15mm below the top of the steerer.
With a soft hammer or mallet, drive star nut straight into
steerer tube until tool contacts top of steerer.
Unscrew tool from star nut.
Use extreme caution when cutting and installing star nut
to avoid injury.
Final Assembly and Adjustment:
Prior to installing the bearing cap on
a threadless steerer tube, round off the top of the steerer
tube to avoid sheering the o-ring on the inside of the bearing
cap.
Re-install o-ring into bearing cap.
Insert fork into frame.
Taking care not to shear o-ring, slide bearing cap, any spacers,
and then stem over steerer tube. Place stem cap on top of
stem and insert screw through cap, threading into star nut.
Tighten approx. 4-10 in.-lb. (Max. 15 in. lb.)
Adjust alignment of stem and secure according to stem manufacturers
specifications.
Check headset for proper adjustment. When properly adjusted,
the fork will rotate smoothly without play or restriction.
Some settling may occur after 1st few rides; readjust if necessary.
If necessary, adjust cap nut and stem bolts as above until
proper adjustment is achieved. NOTE: New seals will produce
some resistance in rotation for the first 50-100 hours of
use. Avoid confusing this with rubbing or binding that may
result from improper installation or stems that are not properly
faced.
A Note on Threadless Stems:
We recommend using stems with a split clamp and either one
or two bolts (preferably two).
It is important to check the bottom face of all threadless
stems. Many are not square to the steerer tube and may cause
headset parts to sit unevenly or rub on the cups.
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Additional Installation Notes for Threaded
Systems:
GRIPNUT™
Size and cut steerer tube:
Insert fork into frame. Steerer tube should protrude 11-14mm
above top of bearing cup. Cut steerer tube if needed.
Clean the steerer tube removing all metal chips, burrs and
grease.
Make sure the thread on the lock ring and the inside thread
of the adjusting ring are lubricated thoroughly with anti-seize
compound or heavy grease. Also apply grease to the tapered
surfaces of the thread collet and lock ring.
Place the thread collet into the threaded hole of the adjusting
ring, positioning the key on the collet in the corresponding
slot.
Screw the lock ring into the adjusting ring/collet assembly
until the collet has very little float inside the assembly.
Final Assembly and Adjustment:
Once the GripNut™ is securely on the steerer tube (about
4-5 turns and at least 1/8" prior to contacting the bearing),
tighten the lock ring into the adjusting ring until it feels
as though the GripNut™ is dragging as it turns on the
threads.
Once you feel this drag, advance the entire GripNut™
as a unit down to touch the bearing (using headset wrenches
on both the lock and adjusting ring if necessary).
Adjust the preload on the bearing and finish tightening the
GripNut™ lock and adjusting rings together to 130-150
in/lb.
TEST: Using both wrenches, try to turn the GripNut™
as a unit in the loosening direction. It should be extremely
difficult, if not impossible, to turn. If it turns easily,
continue to turn the entire unit 1/4 turn in the loosening
direction and re-torque.
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2NUT™
Size and cut steerer tube:
Insert fork into frame.
Thread adjusting nut onto fork.
To size steerer tube length, make sure there are at least
5 full threads above the adjusting nut available for the lock
nut.
Final Assembly and Adjustment:
Adjust our 2Nut™ headset as you would any traditional
lock and adjusting nut headset.
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In general, headset service should be done at least every
two years. In dry climates, service intervals may be longer.
In wet climates, service may be necessary as often as every
6 months.
You may service your Chris King headset while in the frame
using a light solvent based lubricant (e.g., Bullshot aerosol
or WD-40,) to flush the bearings. If you have access to the
correct tools for the proper removal and reinstallation of
Chris King bearing cups, we have found it easier and more
effective to remove the cups and use a solvent tank.
Remove snap ring and seal:
Take a pointed instrument, such as a penknife, insert it at
the split in the snap ring, and lift the pointed end out.
Once the pointed end is free, the remainder of the ring can
be removed easily. Lift out the inner seal. At this point
the bearing will be exposed.
Clean and re-grease the bearings and replace the seal and
snap ring:
With a small brush (e.g., a tooth brush) clean the bearing
while rinsing with solvent. If the bearing has been neglected
and is frozen, let it soak for a few minutes. Then, rotate
the inner race back and forth to work it free. Rinse in solvent
and blow dry with an air hose to remove any excess solvent.
Test the bearing for smoothness. If the bearing was frozen
for too long it may have become damaged or may be too rough
and need replacing. However, if the bearing has lost only
some of its silky smoothness, it may not be evident at the
handlebar once re-greased and reassembled. If bearing replacement
is necessary return cup(s) to us to have a new bearing(s)
installed.
Re-grease the bearings using Bullshot or any other waterproof
grease. Carefully wipe off the inner seal and reinstall. Finally,
insert the pointed end of the snap ring into the snap ring
groove, working it around the bearing until the other end
seats and a small gap is noticed. Inspect the rest of the
parts for any wear. At this time, you are ready to reassemble
the headset and adjust.
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Common questions and the likely solutions:
We are also available to answer your technical service questions
during business hours Monday through Friday at 800.523.6008.
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The steerer tube may be too long and interfering with the
stem cap (threadless) or lock nut (threaded). Solution: Cut
the steerer tube or install spacer(s) so that there is the
necessary clearance.
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1. The bearings may be dirty or frozen. Solution: Service
the bearings.
2. The frame and/or fork and/or stem may not be properly prepped.
This can cause the top or bottom pieces to rub on the cups
or the steerer tube to rub on the inside of the bottom cup.
This is most commonly found on titanium and hard aluminum
frames. Solution: Properly ream and face the frame and/or
fork and/or stem and check for the proper head tube bore size.
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1. The frame and/or fork may not be properly prepped. This
can cause the top or bottom pieces to rub on the cups or the
steerer tube to rub on the inside of the bottom cup. This
is most commonly found on titanium and hard aluminum frames.
Solution: Properly ream and face the frame and/or fork and
check for the proper head tube bore size.
2. If it is a threadless system, the bottom face of the stem
may not be perpendicular to the bore thus causing the bearing
cap to cock and rub the cup. Solution: Face the bottom surface
of stem square with steerer tube.
3. If it is a threaded system, the threads on the steerer
tube may not be straight. Solution: Replace the steerer tube.
4. The bearings may be dirty. Solution: Service the bearings.
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A properly set up Chris King headset shouldn't need adjustment
more than once or twice a year (depending on riding style).
If your headset needs adjustment more often than once a month,
check for the following:
Threadless models:
1. The pinch bolt on the stem may not be tight enough or the
clamp method may be inadequate. We have found that stems with
a split and one or two pinch bolts hold better with less chance
of distorting the steerer tube than internal wedge designs.
Solution: Tighten or replace the stem.
2. Steerer tube may not extend far enough into the stem. Solutions:
1) If spacers are being used to elevate the stem, remove as
necessary to lower the stem to within 3mm of the top of the
steerer tube; 2) Replace the steerer tube and be sure to cut
steerer tube to extend to within 3mm of the top of the stem
(steerer tube must not interfere with the stem cap).
3. Steerer tube may be pulling through the crown. This is
more common with older suspension forks. Solution: Contact
the fork manufacturer to determine the proper remedy for the
steerer tube pulling through the crown. 4. Demanding applications
(such as trials and BMX) can generate strong leverage on the
handlebars and walk the stem up the steerer tube. Solution:
In this case it is best to extend the steerer tube through
and above the stem. Spacers may then be used on top of the
stem to allow proper functioning of the stem cap. (We learned
this trick from the boys at GT BMX racing.)
Threaded models:
(GripNut™)
1. GripNut™ may not be tight enough or may otherwise
be improperly adjusted. If the lock ring was too loose as
the GripNut™ was tightened to adjust the preload on the
bearing, the collet will not clamp properly as the lock ring
is tightened to hold the GripNut™ in place. Solution:
Readjust GripNut™ according to the above instructions.
2. The adjusting ring may be rubbing on top cup due to misalignment
of either the cup or the threads on the steerer tube. Solution:
For misaligned cups, face and ream the frame; for misaligned
threads, replace the steerer tube.
3. GripNut™ lock ring may be bottoming out on the top
of the steerer tube. Solution: Re-cut the steerer tube so
that there is a gap of approximately 1mm below the inner lip
of the lock ring.
(2Nut™)
1. The lock and adjusting nuts may not be locked together
tight enough. Solution: Tighten lock and adjusting nut together.
2. Adjusting nut may be rubbing on the top cup due to misalignment
of either the cup or the threads on the steerer tube. Solution:
For misaligned cups, face and ream the frame; for misaligned
threads, replace the steerer tube.
3. The threads on the fork steerer tube may be undersized
(in pitch diameter). If this is the case the adjusting nut
will fit loosely on the threads. Solutions: 1) Switch to a
GripNut™ top assembly--the GripNut™ will clamp onto
undersize threads; 2) Replace steerer tube; 3) Regenerate
the threads on the existing steerer tube after wishing metal
back.
4. The lock nut may not be threaded far enough onto the steerer
tube. It should thread on a minimum of four full turns to
hold properly. Solutions: 1) Switch to a GripNut™--the
GripNut™ offers a shorter stack height; 2) Replace steerer
tube and cut long enough to allow adequate engagement on the
lock nut.
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Check all of the possible causes for "...loosens quickly,"as
well as:
1. The head tube may be out of parallel. This can cause looseness
due to premature wearing of the conical bearing contact surfaces.
Solution: Properly ream and face the frame and/or fork. Check
conical bearing contact surfaces for excessive wear and replace
if necessary.
2. Cups may be loose in the head tube. This can happen if
the head tube bore is oversize or if the material of the head
tube is extremely soft and/or stretched out. Solutions: 1)
If the head tube is oversize, we may be able to provide cups
with oversize skirts; 2) If the head tube material is soft
and/or stretched, contact the frame manufacturer for possible
remedies.
3. The skirt of the headset cup or the head tube may be cracked.
Solutions: 1) Contact us to replace a cracked cup. Then, check
the head tube bore for proper size and ream if necessary.
Additionally, the head tube bore chamfer may be inadequate
or absent--cut or file according to above instructions; 2)
Contact frame manufacturer regarding a cracked head tube.
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The following components are more often the cause of creaks
and ticking noises than headsets:
Suspension fork:
Steerer tube and crown - both press fit and clamped
Stanchion tubes
Fork brace bolts
Bars, stem, cables
Cracked head tube
If these components are not the source of the noise, check
the following:
1. Improper reaming and/or facing (e.g., cups not parallel)
can cause abnormal wear on the conical bearing contact surfaces
which can cause creaking and/or ticking noises. Solution:
Check and properly ream and face head tube as necessary and
check conical bearing contact surfaces for excessive wear
and replace if necessary.
2. The conical bearing contact surfaces on the base plate
may be completely dry. If the bike is ridden in extremely
wet conditions, ridden or transported in the rain, or washed
with high pressure spray, the lubrication on these surfaces
may have been washed away. Solution: Lay a thin layer of antisieze
on the conical contact surfaces.
3. The base plate may be loose on the crown race seat. This
can result from a stretched base plate or an undersized crown
race seat. Solutions: 1) Replace base plate; 2) Contact us
for an undersized base plate.
4. The cup(s) may be loose in the frame. Solution: Contact
us for possible oversized cups.
5. The head tube bore may be "bell mouthed". The
cups then press fit only at the innermost ends. Solutions:
Contact us with an accurate measurement of the head tube and
the extent of the "bell" and we may be able to provide
oversize cups that work in the head tube. If the degree of
bell mouth is extremely pronounced, you may need to contact
the frame manufacturer for possible remedies.
6. The bearings may be dirty or seized. Solution: Service
the bearings.
7. On a NoThreadSet™, the bottom surface of the stem
may be sliding on the bearing cap. This can happen if the
o-ring is sheered in installation. Solution: Replace the O-ring
and file the top of steerer tube to prevent sheering upon
reinstallation of the bearing cap. Apply anti-sieze to the
bottom of the stem where it contacts the bearing cap.
8. The steerer tube may be undersize. Steerer tubes should
be ±.025mm (.001") of the nominal size. We often
see steerer tubes as much as .25mm (.010") undersize.
Solution: Replace the steerer tube.
9. Bottom surface of stem may not be flat. Solution: Face
bottom of the stem.
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