Specialized AETHOS User manual

USER MANUAL

CONTENTS
1. INTRODUCTION .................................................................................................................... 1
1.1. INTENDED USE ....................................................................................................................................................................1
1.2. WARRANTY .........................................................................................................................................................................1
2. GENERAL NOTES ABOUT ASSEMBLY................................................................................... 2
2.1. TOOLS / TORQUE SPECS...................................................................................................................................................3
3. GENERAL NOTES ABOUT MAINTENANCE............................................................................. 3
4. SPECIFICATIONS................................................................................................................. 4
4.1. GEOMETRY .........................................................................................................................................................................4
4.2. SMALL PARTS SPECIFICATIONS (COMMON PARTS)...................................................................................................6
4.3. SMALL PARTS SPECIFICATIONS (MECHANICAL COMPATIBLE FRAMES)................................................................6
4.4. SMALL PARTS SPECIFICATIONS (S-WORKS MODELS) ..............................................................................................6
5. BRAKE/SHIFT ASSEMBLY ................................................................................................... 7
5.1. FRONT DERAILLEUR HANGER INSTALLATION (S-WORKS ONLY)..............................................................................7
5.2. SHIFTING - ELECTRONIC WIRED SYSTEM ....................................................................................................................10
5.3. SHIFTING - MECHANICAL SYSTEM (MECHANICAL COMPATIBLE MODELS ONLY).................................................12
5.4. DISC BRAKES.....................................................................................................................................................................14
6. SEATPOST ASSEMBLY......................................................................................................... 15
7. FORK / STEM ASSEMBLY..................................................................................................... 17
We may occasionally issue updates and addendums to this document. Please periodically check www.specialized.com or contact Rider Care to
make sure you have the latest information.
Info: specialized.com / 877-808-8154
SPECIALIZED BICYCLE COMPONENTS
15130 Concord Circle, Morgan Hill, CA 95037 [phone]
0000149312_UM_R1, 04/20

1
1. INTRODUCTION
This user manual is specific to your Specialized Aethos bicycle. It contains important safety,
performance and technical information, which you should read before your first ride and keep
for reference. You should also read the entire Specialized Bicycle Owner’s Manual (“Owner’s
Manual”), because it has additional important general information and instructions which you
should follow. If you do not have a copy of the Owner’s Manual, you can download it at no
cost at www.specialized.com, or obtain it from your nearest Authorized Specialized Retailer or
Specialized Rider Care.
Additional safety, performance and service information for specific components such as
seatpost or pedals on your bicycle, or for accessories such as helmets or lights, may also
be available. Make sure that your Authorized Specialized Retailer has given you all the
manufacturers’ literature that was included with your bicycle or accessories. If there is a
difference between the instructions in this manual and the information provided by the
component manufacturer, please refer to your Authorized Specialized Retailer.
When reading this user manual, you will note various important symbols and warnings, which
are explained below:
WARNING! The combination of this symbol and word indicates a potentially
hazardous situation which, if not avoided, could result in serious injury or
death. Many of the Warnings say “you may lose control and fall.” Because
any fall can result in serious injury or even death, we do not always repeat
the warning of possible injury or death.
CAUTION: The combination of the safety alert symbol and the word CAUTION
indicates a potentially hazardous situation, which, if not avoided, may result
in minor or moderate injury, or is an alert against unsafe practices.
The word CAUTION used without the safety alert symbol indicates a situation
which, if not avoided, could result in serious damage to the bicycle or the
voiding of your warranty.
INFO: This symbol alerts the reader to information which is particularly
important.
GREASE: This symbol means that high quality grease should be applied as
illustrated.
CARBON FRICTION PASTE: This symbol means that carbon friction paste
should be applied as illustrated to increase friction.
TORQUE: This symbol highlights the correct torque value for a specific bolt.
In order to achieve the specified torque value, a quality torque wrench must
be used.
TECH TIP: Tech Tips are useful tips and tricks regarding installation and use.
1.1. INTENDED USE
The Specialized Aethos bicycles are intended and tested for High Performance Road Riding use
only (condition 1). For more information on intended use and structural weight limits for the frame
and components, please refer to the Owner’s Manual.
1.2. WARRANTY
Please refer to the written warranty provisions provided with your bicycle, or visit www.
specialized.com. A copy is also available at your Authorized Specialized Retailer.

2
2. GENERAL NOTES ABOUT ASSEMBLY
This manual is not intended as a comprehensive assembly, use, service, repair or maintenance
guide. Please see your Authorized Specialized Retailer for all service, repairs or maintenance.
Your Authorized Specialized Retailer may also be able to refer you to classes, clinics or books
on bicycle use, service, repair, and maintenance.
Tire sizes vary significantly from brand to brand. CEN standards require a minimum of 6mm
of clearance between the frame/fork and the tires. When choosing a wheel and tire combo,
factor in enough clearance for the conditions, setup and wheel flex.
The Aethos frames use a 68mm standard BSA threaded design. Grease the threads. Install
and torque according to the bottom bracket manufacturer’s instructions.
Before installing the bottom bracket and crank, make sure all housings and wires are
routed through the frame.
The Aethos frame is available in two frame configurations, 12R (S-Works
models) and 10R (all other models).
The 12R frames are compatible with electronic shifting systems only. A custom
backing plate is required to mount the front derailleur hanger. Information
specific to 12R frames is covered in section 5.1 (highlighted in BLUE).
The 10R frames are compatible with electronic or mechanical shifting
systems. Information specific to mechanical shifting system installation is
covered in section 5.3 (highlighted in ORANGE).
WARNING! Never modify your frame or components in any way. Do not sand,
drill, file, or remove parts. Do not install incompatible forks or components.
An improperly modified frame, fork, or component, can cause you to lose
control and fall.
In order to successfully build the Aethos bicycle, it is very important to follow
the order of operations as outlined in this manual. Modifying the order of
assembly will result in a longer build process.
Assembly of the front end of the bicycle is easiest with the rider’s fit already
determined (the steerer tube doesn’t need to be cut at this time, it can stick
out the top of the stem), prior to routing all the housings and wires through the
frame and fork.
To determine fit, it is recommended to use a fit tool. If this is not possible,
perform a basic assembly of the wheels, drivetrain and front end components,
without the brakes and housings. Once the fit is complete, all the components
will have to be removed in order to route the housings and wires.
WARNING! Due to the high degree of complexity of the Aethos, proper assembly
requires a high degree of mechanical expertise, skill, training and specialty tools.
Therefore, it is essential that the assembly, maintenance and troubleshooting be
performed by an Authorized Specialized Retailer.
WARNING! Many components on the Aethos, including, but not limited to, the
handlebars and the stem, are proprietary to the Aethos. Only use originally
supplied components and hardware at all times. Use of other components or
hardware will compromise the integrity and strength of the assembly. Aethos
specific components should only be used on the Aethos and not on other
bicycles, even if they fit. Failure to follow this warning could result in serious
injury or death.
CAUTION: Do not face the bottom bracket shell! This can prevent proper
installation of the crank. Your Specialized frame does not require any bottom
bracket shell pre-installation preparation, as all surfaces have been precisely
machined to specific tolerances at the factory for proper interface with a
compatible crankset. Please refer to the manufacturer instructions for crank
and bottom bracket installation.
CAUTION: Always use a bottom bracket equipped with a sleeve between the
two cups. Running a bottom bracket without the sleeve can result in housings
and/or wires contacting the bottom bracket spindle, which can result in wear.

3
2.1. TOOLS / TORQUE SPECS
WARNING! Correct tightening force on fasteners (nuts, bolts, screws) on your
bicycle is important for your safety. If too little force is applied, the fastener
may not hold securely. If too much force is applied, the fastener can strip
threads, stretch, deform or break. Either way, incorrect tightening force can
result in component failure, which can cause you to lose control and fall.
Where indicated, ensure that each bolt is torqued to specification. After your
first ride, and consistently thereafter, recheck the tightness of each bolt to
ensure secure attachment of the components. The following is a summary of
torque specifications in this manual:
CAUTION: Ensure that all contact surfaces are clean and bolt threads are
greased or have a threadlocking compound (refer to the instructions for each
bolt) prior to installation.
The following tools are required for installation of this product:
2, 2.5, 3, 4, 5, 6mm socket-style Allen key bits
Torque wrench
High-quality grease
Cable housing cutters
Carbon assembly compound (fiber paste)
Blue threadlocker
3. GENERAL NOTES ABOUT MAINTENANCE
The Aethos is a high performance bicycle. All regular maintenance, troubleshooting, repair
and parts replacement must be performed by an Authorized Specialized Retailer. For general
information regarding maintenance of your bicycle, please refer to the Owner’s Manual. In
addition, routinely perform a mechanical safety check before each ride, as described in the
Owner’s Manual.
Great care should be taken to not damage carbon fiber or composite material. Any damage
may result in a loss of structural integrity, which may result in a catastrophic failure. This
damage may or may not be visible in inspection. Before each ride, and after any crash,
you should carefully inspect your bicycle for any fraying, gouging, scratches through the
paint, chipping, bending, or any other signs of damage. Do not ride if your bicycle shows
any of these signs. After any crash, and before you ride any further, take your bicycle to an
Authorized Specialized Retailer for a complete inspection.
While riding, listen for any creaks, as a creak can be a sign of a problem with one or more
components. Periodically examine all surfaces in bright sunlight to check for any small
hairline cracks or fatigue at stress points, such as welds, seams, holes, and points of
contact with other parts. If you hear any creaks, see signs of excessive wear, discover any
cracks, no matter how small, or any damage to the bicycle, immediately stop riding the
bicycle and have it inspected by your Authorized Specialized Retailer.
Lifespan and the type and frequency of maintenance depends on many factors, such as
frequency and type of use, rider weight, riding conditions and/or impacts. Exposure to
harsh elements, especially salty air (such as riding near the ocean or in the winter), can
result in galvanic corrosion of components such as the crank spindle and bolts, which
can accelerate wear and shorten the lifespan. Dirt can also accelerate wear of surfaces
and bearings. The surfaces of the bicycle should be cleaned before each ride. The bicycle
should also be maintained regularly by an Authorized Specialized Retailer, which means
it should be cleaned, inspected for signs of corrosion and/or cracks and lubricated. If you
notice any signs of corrosion or cracking on the frame or any component, the affected item
must be replaced.
Regularly clean and lubricate the drivetrain according to the drivetrain manufacturer’s
instructions.

4
Do not use a high pressure water spray directly on the bearings. Even water from a garden
hose can penetrate bearing seals and crank interfaces, which can result in increased
bearing and crank wear, which can affect the normal function of the bearings. Use a clean,
damp cloth and bicycle cleaning agents for cleaning.
Do not expose the bicycle to prolonged direct sunlight or excessive heat, such as inside a car
parked in the sun or near a heat source such as a radiator.
WARNING! Failure to follow the instructions in this section may result in damage
to the components on your bicycle and will void your warranty, but, most
importantly, may result in serious personal injury or death. If your bicycle exhibits
any signs of damage, do not use it and immediately bring it to your Authorized
Specialized Retailer for inspection.
A
B
M
C
D
P
E
F
G
H
I
J
K
L
N
O
4. SPECIFICATIONS
4.1. GEOMETRY
FRAME SIZE 49 51 54 56 58 61
A STACK (MM) 514 527 544 565 591 612
B REACH (MM) 375 380 384 395 402 408
C HEAD TUBE LENGTH (MM) 109 120 137 157 184 204
D HEAD TUBE ANGLE (°) 71.75 72.5 73 73.5 73.5 74
E BB HEIGHT (MM) 266 268
F BB DROP (MM) 74 72
G TRAIL (MM) 63 58 55 52
H FORK LENGTH, FULL (MM) 369
I FORK RAKE/OFFSET (MM) 47 44
J FRONT CENTER (MM) 574 577 579 591 606 613
K CHAINSTAY LENGTH (MM) 410
L WHEELBASE (MM) 973 975 978 991 1005 1012
M TOP TUBE LENGTH, HORIZONTAL (MM) 508 531 540 562 577 595
N BIKE STANDOVER HEIGHT (MM) 776 800 818 839 866 894
O SEAT TUBE LENGTH (MM) 431 462 481 504 532 567
P SEAT TUBE ANGLE (°) 75.5 74 73.5 73

5
GREASE
B
D
E
L
L
M
N
O
P
Q
R
TS
U
F
G
H
I
J
A
C
K
V
W
X
Y
MECHANICAL COMPATIBLE
FRAMES ONLY (10R)
*S-WORKS
ONLY (12R)
ELECTRONIC
SHIFTING ONLY
Ca
SMALL PARTS EXPLODED VIEW

6
4.2. SMALL PARTS SPECIFICATIONS (COMMON PARTS)
The S-Works models are compatible with electronic shifting only (wired or wireless). All other
models are compatible with electronic or mechanical shifting systems.
PART # DESCRIPTION TOOL SIZE in-lbf Nm
AFRAME
BFORK
CS201900005 *FRONT DERAILLEUR (FD) HANGER 2.5mm 18 2.0
DS201900002 RUBBER FD BLOCK OFF PLATE
ES206000001 REAR DERAILLEUR (RD) HANGER 4mm 40 4.5
FS174700006 SEAT COLLAR 4mm 55 6.2
GS204900004
SEATPOST (FRONT RAIL CLAMP BOLT) 4mm 26.5 3.0
SEATPOST (REAR RAIL CLAMP BOLT) 5mm 55 6.2
HS186800006 Di2 BATTERY SLEEVE
I
S200200010 FRONT AXLE 6mm 133 15.0
J
S200200011 REAR AXLE 6mm 133 15.0
K
WATER BOTTLE 3mm 25 2.8
L
S179900013 CABLE HOUSING FERRULE
M
S202500013 STEM TOP CAP 4mm
N
S202500012
HEADSET COVER
O
COMPRESSION RING
P
UPPER HEADSET BEARING
Q
LOWER HEADSET BEARING
R
S202500011 EXPANDER PLUG 6mm 55 5.1
S
S209900054 REAR DERAILLEUR PLUG (WIRED)
T
S179900015 REAR DERAILLEUR PLUG (WIRELESS)
U
S200700001 FRONT BRAKE CALIPER PLATE
4.3. SMALL PARTS SPECIFICATIONS (MECHANICAL COMPATIBLE FRAMES)
PART # DESCRIPTION TOOL SIZE in-lbf Nm
V
S186500003 DOWN TUBE ICR COVER PLATE 2.5mm 7 0.8
W
S186500004 DOWN TUBE ICR MECHANICAL PORT 2.5mm 7 0.8
X
S206500011 BOTTOM BRACKET CABLE GUIDE
Y
S172000002 CHAINSTAY CABLE GUIDE 3mm 25 2.8
4.4. SMALL PARTS SPECIFICATIONS (S-WORKS MODELS)
PART # DESCRIPTION TOOL SIZE in-lbf Nm
C
S201900005
*FRONT DERAILLEUR (FD) HANGER 2.5mm 18 2.0
Ca FRONT DERAILLEUR HANGER
BACKING PLATE
The Aethos frame is available in two frame configurations, 12R (S-Works
models) and 10R (all other models).
The 12R frames are compatible with electronic shifting systems only. A custom
backing plate is required to mount the front derailleur hanger. Information
specific to 12R frames is covered in section 5.1 (highlighted in BLUE).
The 10R frames are compatible with electronic or mechanical shifting
systems. Information specific to mechanical shifting system installation is
covered in section 5.3 (highlighted in ORANGE).
Many bolts have a blue threadlock patch on the threads to help secure the
bolt under torque. Repeated installation and removal of a bolt may reduce the
effectiveness of the patch. However, it can be replaced with the application of
a liquid blue threadlocker.
*Part C (Front derailleur hanger): The same hanger is used on all models.
However, the S-Works model also requires a backing plate. For additional
information, refer to section 5.1.

7
5. BRAKE/SHIFT ASSEMBLY
5.1. FRONT DERAILLEUR HANGER INSTALLATION (S-WORKS ONLY)
2
SHIFT CABLE
HEAD
SHIFT
CABLE
HANGER
BACKPLATE
1
SHIFT CABLE
SHEATH
The front derailleur hanger on all models is the
same. However, the S-Works model requires
the installation of a backing plate, while all other
models use rivets integrated into the frame.
S-WORKS (12R) FRAMES: The front derailleur hanger is
mounted by inserting bolts through the hanger and threading
them into the backing plate. This backing plate must be held in
position while installing the screws. To hold the mounting plate
in position, follow the steps below:
FIG. 1: Insert a shift cable sheath through the upper bolt hole
and out the bottom bracket shell.
FIG. 2: Insert a shift cable through the backside of the
backing plate, then guide the shift cable up the cable sheath
until the cable exits the upper front derailleur bolt hole.

8
3
SHIFT CABLE
HEAD
4 5
FIG. 3: Pull on the cable exiting the bolt hole, while guiding the backing plate up into the seat tube, until it rests against the inside of the seat tube.
FIG. 4: Guide the front derailleur hanger over the cable, then with the cable still pulled taut, thread the lower bolt into the backing plate.
If a Di2 wire will be installed, keep the lower bolt loose while still threaded into the backing plate, while keeping the cable in place, rotate the front derailleur hanger out of
position so the wiring hole is exposed, then guide the wire through the seat tube and backing plate hole until it exits the bottom bracket shell.
FIG. 5: Remove the cable by guiding it down the seat tube, then thread the upper bolt into the backing plate.

9
1
750mm - TO REAR
DERAILLEUR
500mm - TO FRONT
DERAILLEUR
S209900054
1000mm - TO BATTERY
SM-JC41 JCT B BOX
1400mm - TO JCT A BOX
5.2. ELECTRONIC WIRING ROUTING

10
5.2. SHIFTING - ELECTRONIC WIRED SYSTEM
FRAME WIRING LENGTHS:
LOCATION QTY LENGTH
JCT B BOX TO COCKPIT (SHIFTER) 1 1400mm
JCT B BOX TO REAR DERAILLEUR 1 750mm
JCT B BOX TO FRONT DERAILLEUR 1 500mm
JCT A BOX TO BATTERY (SEATPOST) 1 1000mm
FIG. 1 (Shimano Di2): Route the wires through the frame.
• Route a 1400mm wire from the head tube ICR port, down the down tube and out the bottom bracket
hole.
The Di2 wire must be routed into the down tube before the rear brake housing.
• Route a 750mm wire starting from the chainstay port and out the bottom bracket hole.
• Route a 500mm wire starting from the seat tube front derailleur port and out the bottom bracket hole.
To insert the front derailleur wire, follow the steps in section 5.
• Route a 1000mm wire down from the top of the seat tube and out the bottom bracket hole.
• Install the grommets and clips on the battery, then install the battery/grommet assembly in the seatpost.
• Plug the 1000mm battery wire into the battery, then install the seatpost as described section 6,
page 15.
• Plug the four wires exiting the bottom bracket shell into a Junction B box, then place the Junction B
box and the wires in front of the bottom bracket shell.
To prevent the JCT B box from rattling, wrap the box in a bit of foam before
placing it in front of the bottom bracket shell.

11
5.3. MECHANICAL CABLE ROUTING
(Mechanical compatible models only)
1
S172000002
S206500011
S186500004
CABLES CROSS
CABLES CROSS

12
5.3. SHIFTING - MECHANICAL SYSTEM (MECHANICAL COMPATIBLE MODELS ONLY)
2
FIG. 2: Install the cable guides.
• Install the down tube cable guide (S186500004) in the down tube ICR port.
• Install the chainstay cable guide (S172000002) on the chainstay.
3
FRONT
REAR
FIG. 3: Install the cable housings.
• Install the cable sheaths in the cable guide followed by the front and rear shift housings, then trim
and install according to the manufacturer’s instructions.
It is recommended to route the shift housings from the shifters to their
opposing ports on the downtube ICR port (fig. 1), then cross the cables inside
the down tube before going through the bottom bracket cable guide.
• Install a section of rear derailleur housing from the rear derailleur to the chainstay cable housing stop,
then trim and install according to the manufacturer’s instructions.
• Insert the cables in the shifters, then guide them down the down tube until they exit at the bottom
bracket ICR port.
4
FIG. 4: Install the bottom bracket cable guide.
• Determine which cable is which, then insert the rear shift cable in the drive side hole of the bottom
bracket cable guide (S206500011) and front shift cable in the non-drive side hole.
• Place the bottom bracket cable guide in its cavity under the bottom bracket shell, then route the
shift cables to their derailleurs.
• Finish installing the shift cables according to the manufacturer’s instructions.

13
1
CHURRO (Foam sleeve)
S179900013
S179900013
S200700001
A
B
1a
S200700001
5.4. DISC BRAKE ROUTING

14
5.4. DISC BRAKES
FIG. 1: Route the rear brake housing.
• Run the rear brake housing in through the chainstay ICR port, over the bottom bracket shell, up the
down tube.
• Install a Churro (foam sleeve) over the brake housing and into the down tube.
• Route the brake housing out the head tube ICR port.
• Install a grommet over the brake housing and into the head tube ICR port.
• Install the caliper on the chainstay. Complete the rear brake installation according to the brake
manufacturer’s instructions.
FIG. 1: Route the front brake housing.
• Run the front brake housing in through the lower ICR port in the fork and guide it up the fork leg until
it exits at the ICR port on the fork crown.
• Install a grommet over the brake housing and into the upper fork ICR port.
• FIG. 1a: Install the caliper on the Specialized Flat Mount front brake adapter (A), then bolt the
adapter to the fork mount holes (B).
FIG. 1a: Only use the Specialized Flat Mount front brake adapter
(S200700001) on the Aethos fork.
• Complete the front brake installation according to the brake manufacturer’s instructions.

15
6. SEATPOST ASSEMBLY
1
ITEM DESCRIPTION
A M6 BOLT
B M6 CRADLE WASHER
C M6 BARREL NUT
D M5 BOLT
E M5 CRADLE WASHER
F M5 NUT
E
B
A
D
F
C
FIG. 1: Install the saddle.
• Grease then install the M6 barrel nut inside the seatpost.
• Grease and assemble the M6 bolt and M6 cradle washer, then install them in the upper cradle.
• Install the lower cradle, followed by the saddle (with greased rails) and upper cradle assembly.
• Grease and assemble the M5 bolt and M5 cradle washer, then install the bolt and spacer through the
seatpost bolt hole and through the lower cradle.
• Grease then install the M5 nut onto the M5 bolt.
• Adjust the saddle fore-aft position, then adjust the angle of the saddle by turning the M6 bolt.
• Torque the M5 bolt, then check the saddle angle. If the angle still needs to be adjusted, loosen the M5
bolt, loosen or tighten the M6 bolt accordingly, then torque the M5 bolt again. Repeat until the saddle is
at the desired angle.
2
FIG. 2: Install the seatpost in the frame.
• Make sure the seat collar is facing toward the front of the bike.
• If using Shimano Di2, install the battery in the seatpost using the grommet assembly
(S186800006), then plug the seat tube wire into the battery.
• Apply carbon assembly compound (fiber paste), then insert the seatpost into the seat tube.

16
MI
N
INSE
R
TIO
N
3
FRAME MINIMUM
INSERTION:
75mm FROM TOP OF
COLLAR
MAXIMUM
INSERTION
SEATPOST
MINIMUM
INSERTION
FIG. 3: Determine the saddle height.
• Both the frame and seatpost have minimum insertion requirements. In addition, the frame has a
maximum insertion requirement to prevent damage to the tire cutout area.
• MINIMUM INSERTION: The seatpost must be inserted into the frame deep enough so the
minimum insertion/maximum extension (min/max) mark on the seatpost is not visible. The frame
requires a minimum of 75mm of insertion.
• MAXIMUM INSERTION: The seat tube can accommodate up to 215mm of seatpost insertion.
• If the post is at the minimum or maximum insertion and the saddle is not at the desired position, the
seatpost must be replaced with a longer or shorter seatpost.
• Fig. 2: Once the saddle height is determined torque the seat collar bolt to 55 in-lbf (6.2 Nm).
The Aethos seatpost is available in two lengths (300mm and 360mm). If the
360mm post is too long, we recommend using the 300mm seatpost.
Do not apply grease to the contact surfaces between the seatpost and the
seat tube. Grease reduces the friction, which is critical to proper seatpost grip.
Specialized recommends the application of carbon assembly compound (fiber
paste), which can increase friction between carbon surfaces. Please visit your
Specialized Authorized Retailer for additional information.
WARNING! Failure to follow the seatpost and frame insertion requirements
(fig. 3) may result in damage to the frame and/or seatpost, which could
cause you to lose control and fall.
WARNING! For general instructions regarding the installation of the seatpost,
refer to the appropriate section in the Owner’s Manual. Riding with an
improperly tightened seatpost can allow the saddle and seatpost to slide down,
which can damage the frame and cause you to lose control and fall.
WARNING! Inspect the seatpost and seat tube to ensure that there are no burrs
or sharp edges. Remove any burrs or sharp edges using fine grit sandpaper.

17
7. FORK / STEM ASSEMBLY
1
HEADSET COVER
COMPRESSION RING
UPPER BEARING
LOWER BEARING
EXPANDER PLUG
FIG. 1: Install the headset and stem.
• Install the front end (fork, headset, headset spacers, stem, handlebar, wheels) on the frame then
determine the rider’s fit. Do not install more than 35mm of spacers between the stem and the
headset cover (fig.2).
• Trim the steerer tube so the final cut is 3mm below the top of the stem (or 3mm below the top of the
spacer if a 5mm spacer is used).
• Install the steerer tube expander plug, then torque the plug to 45 in-lbf / 5.1 Nm.
• When installing the headset for the final assembly, grease the bearings and compression ring.
• Install the headset cover, spacers and stem, followed by the top cap and bolt.
• Once the bike is fully assembled, adjust the headset, using the front brake to determine if there’s any
headset looseness.
Placing more than 5mm of stem spacers above the stem is acceptable for
fit purposes only. For actual riding, the stem requires full support from the
expander plug inside the fork to function safely and as intended.
Once the bike’s fit has been determined, the steerer tube should be cut 3mm
below the top of the stem. Alternatively, no more than one 5mm spacer can be
placed above the stem (fig. 2).
If a 5mm spacer is used, cut the steerer tube 3mm below the top of the 5mm
spacer.
WARNING! The stem must be fully supported by the expander plug. The
maximum combined height of the stem and optional 5mm spacer (from bottom
of stem to top cap) must not exceed 45mm. Exceeding 45mm can result in an
insufficiently supported stem, which can cause the steerer tube to fail.
ALPINIST COCKPIT: Please note the Roval Alpinist steerer tube clamp is 45mm
tall. To ensure full support from the expander plug, no spacers can be installed
above the stem.
WARNING! Do not apply grease or carbon assembly compound (carbon paste)
between the stem and the steerer tube, and do not twist the stem onto the
steerer tube. This can result in damage to the composite surface, which may
result in a catastrophic failure of the fork, resulting in serious personal injury
or death.
CAUTION: The Aethos is supplied with one 5mm solid spacer (consistent inner
diameter) and 35mm of scalloped spacers.
Only use the 5mm solid spacer above the stem, between the stem and the top cap.
Only use the 5mm and 10mm scalloped spacers below the stem, between the
stem and the headset cover.