TechServiceManual

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Te c hnical Service Manual
for Shop Mechanics
rev. 10/04
Complete instructions for servicing all
Chris King headsets and hubs.
Includes answers to common technical questions
and use of the Chris King hub service tool.
King Cycle Group
2801 NW Nela Street; Portland, Oregon 97210
For technical questions, call 800.523.6008
www.chrisking.com
H
EADSETS
This manual is intended for the mechanic who already possesses a familiarity with headset
installation technique and who is interested in the finer points of both proper headset set-up
and troubleshooting for best headset performance.
F
EATURES
•en year warranty
• Unparalleled quality, reliability, and reputation
• In-house design and manufacturing - 100% made by Chris King in the USA
•Available in all standard sizes and our new and exclusive Devolution
™
size (to adapt 1-1/8”
forks to 1-1/4” frames).
• Unique modular design offers affordable upgrades and outlasts changing fork trends
• Exceptionally lightweight
• Over 24 years of experience
P
REPARATION
AND
I
NSTALLATION
F
RAME
P
REPARATION
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 headtube
facing and reaming before installation.
1. Ream and face the head tube as necessary to ensure
that the head tube is faced square and bored to the
proper dimensions. (See table 1 - next page.)
2. Using a small file, sand paper, or deburring tool,
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 metal from
the cups during installation. (See figure 1.)
Figure 1 - deburr headtube
Rev. 10/04-A
3
3. Clean to remove any chips, shavings, and/or cutting
oil.
4. The proper press fit should be with no more than
.1mm (.004") of interference. See table 1 for
correct headtube bore size.
H
bb b bb
C
s
OOOOO
D
1
3
2
1
B
3
2
1
3
3
3
3
1
1
D
3
3
Facing tolerances
table 1 - frame prep specs
We recommend that the variation in parallelness of the end faces of the headtube not 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 headtube 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 ensure proper alignment. Cut metal as necessary until all of the
ink is removed.
Bore sizing
Most reamers are .2mm under the nominal cup size and 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 while the reamer is in the bore, the reamed bore may become
oversized. Some manufacturers have included bushings that take the place of the reamer to
prevent continued reaming while facing. If these are available, they should be used.
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 shouldn’t be
necessary to “reef” 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.) If the cups press in with little resistance or the bore otherwise appears oversized,
oversized cups are available directly from King Cycle Group.
Additional notes on head tube preparation
One 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. (See figure 1 - last
page.) 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.
4
Rev. 10/04-A
t
F
ORK
P
REPARATION
1. Reaming and facing of the fork may be necessary,
but is not critical unless it is grossly out of square or
oversize. The crown race seat should be square 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.
2. Clean to remove any chips, shavings, and/or cutting
oil.
3. The proper press fit should be with no more than
.1mm (.004") of interference. See table 1 above for
correct crown race seat size.
4. Slide the base plate, conical side up, onto the steerer
tube. With the beveled side of the base plate
installation adaptor against the base plate, use a
crown race setting tool to set the base plate. The
base plate installation adaptor helps to protect the
conical bearing contact surface on the base plate
from damage due to impact from the crown race
installation tool. (See figure 2.)
Figure 2 - setting the baseplate
Threadless forks - NoThreadSet
™
Cut steerer tube and install star-nut
1. Insert fork into frame.
2. 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.
3. Remove stem and mark another line 3mm below the
first. Cut on the lower line with a hacksaw.
Do not
use a pipe cutter.
A pipe cutter will swell the end
of the tube, making installation of the bearing cap
and other tight fitting parts difficult.
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.
Figure 3 - starnut installation tool
4. Remove all sharp edges from inside and outside of steerer tube. With a small file or
sandpaper, round outside edge of tube to avoid shearing the o-ring upon installation.
5. Thread star-nut onto installation tool.
6. With a soft hammer or mallet, drive star-nut straight into steerer tube until tool contacts top
of steerer tube. (See figure 3.)
Rev. 10/04-A
5
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