All information and specifications are subject to change for product improvement without notice.
2006 Cannondale Bicycle Corporation - All Rights Reserved
CANNONDALE USA (CUSA)
Cannondale Bicycle Corporation
172 Friendship Road
Bedford, Pennsylvania 15522
CANNONDALE AUSTRALIA (CA)
Unit 6, 4 Prosperity Parade
Warriewood N.S.W 2102
Phone: (02) 9979 5851
Fax: (02) 9979 5688
CANNONDALE JAPAN (CJ)
5-cho Sakai City
Osaka, Japan 590-0132
CANNONDALE EUROPE (CE)
mail: Postbus 5100
visits: Hanzepoort 27
7570 GC Oldenzaal
(Voice): + 41 61.4879380
Carbon Road Fork, Stem and Headset Service Instructions
Our Carbon Forks Use Aheadset System
This design saves weight by eliminating the quill, wedge and
clamping bolt used in a traditional stem system. In the Aheadset
design, a hollow stem clamps to the outside of the fork steering
tube. This stem clamp also serves to hold the proper bearing
preload in the headset. One can think of the stem as also
replacing the lock nut in a traditional headset design.
Cannondale Star Nut & Top Cap System
So how do we achieve proper bearing preload on the Aheadset
bearings? We do not have the threaded upper bearing cup used
in a traditional headset to make this adjustment. The top cap,
bolt, and star nut placed within the steering tube controls the
headset bearing preload. The bolt is tightened just enough to
gain the proper preload, then the stem clamp bolts are tightened
securing the fork inside the head tube. Because the lower edge
of the stem bears on the upper headset bearing race, it holds this
adjustment. Once the bearing preload is set, and the stem clamp
bolts are tightened, the star nut and bolt do no work.
Understanding the System
The Star Nut
In a star nut system, the top cap, inserted inside a steerer tube,
enables the preload of the headset bearings to be set. On forks
with metal or "alloy" steering tubes this is still the only role of the
Long Cylindrical Top Cap
For Cannondale forks with carbon fiber composite steering tubes,
we have designed special long cylindrical top caps. These work as
part of the Star nut system. But they have another very important
role. These metal tubes fit closely within the carbon steering tube
inside diameter, supporting it against the clamping force of the
stem. The long cylindrical shape supports the clamping force of
A System Working Together
It is very important that the proper top cap be used. See the chart
in this document. The O.D. of the top cap must fit very snugly
inside the I.D. of the steerer. It is very important that no spacers
ever be installed above the stem, since this will raise the top cap
and may allow the stem to crush the steerer tube.
Many of the headset compression devices on the market do not
extend far enough down into the steerer tube, and thus do not
support the clamping force from the bottom stem bolt.
Use the Cannondale star nut tool - KT014/ to install the star nut.
MAKE SURE the star nut depth is correct for the fork. See table.
DO NOT EXCEED the MAXIMUM STACK HEIGHT for the fork. See table.
Exceeding this height will place excessive stress on the steerer tube
with risk of fork failure.
DO NOT INSTALL wedge compression or expansion devices. Use only the
Cannondale kit. See table.
DO NOT INSERT spacers between the top of the stem and top cap.
You Must Use a Torque Wrench
Stem clamp bolts, both for the steering tube and handlebars,
must be torqued per the stem manufacturers specifications.
Modern lightweight designs are permanently marked with
proper torque specifications. These must be followed. Over
tightening may cause damage and lead to a failure.
IDENTIFY THE FORK BEFORE YOU BEGIN ANY WORK:
See table on page 2. to
determine the correct
Cannondale top cap and
star nut kit # for the fork.
This document may include procedures beyond the scope of general
mechanical aptitude. Special tools, skills, and knowledge may be
required. Improper mechanical work increases the risk of an accident.
Any bicycle accident has risk of serious injury, paralysis or death.
To minimize risk we strongly recommend that owners always have
mechanical work done by an authorized Cannondale retailer.