KONA OWNER’S MANUAL
KONA OWNER’S MANUAL
38 39
2. Perspective
T oday’ s high-performance bicycles require frequent and
careful inspection and service. In this Appendix we try
to explain some underlying material science basics and
how they relate to your bicycle. W e discuss some of the
trade-offs made in designing y our bicycle and what you
can expect from your bicycle; and we pro vide important,
basic guidelines on how to maintain and inspect it. W e
cannot teach you everything y ou need to know to prop-
erly inspect and service your bicycle; and that is wh y we
repeatedly urge you to take y our bicycle to your dealer for
professional care and attention.
WARNING: Frequent inspection of your bike is
important to your safety. Follow the Mechanical Safety
Check in Section 1.C of this Manual before every ride.
Periodic, more detailed inspection of your bicycle is
important. How often this more detailed inspection is
needed depends upon you. You, the rider/owner, have
control and knowledge of how often you use your bike,
how hard you use it and where you use it. Because
your dealer cannot track your use, you must take re-
sponsibility for periodically bringing your bike to your
dealer for inspection and service. Your dealer will help
you decide what frequency of inspection and service is
appropriate for how and where you use your bike. For
your safety, understanding and communication with
your dealer, we urge you to read this Appendix in its
entirety. The materials used to make your bike deter-
mine how and how frequently to inspect. Ignoring this
WARNING can lead to frame, fork or other component
failure, which can result in serious injury or death.
A) UNDERST ANDING MET ALS
Steel is the traditional material for building bicy cle frames.
It has good characteristics, but in high performance
Appendix B
The Lifespan of Y our Bike and its Components
1. Nothing Lasts Forever, Including Your Bike
When the useful life of your bike or its components is
over , continued use is hazardous.
Every bicycle and its component parts ha ve a nite, limited
useful life. The length of that life will vary with the construc-
tion and materials used in the frame and components; the
maintenance and care the frame and components receiv e
over their life; and the type and amount of use to which the
frame and components are subjected. Use in competitiv e
events, trick riding, ramp riding, jumping, aggressiv e riding,
riding on severe terrain, riding in sev ere climates, riding
with heavy loads, commercial activities and other types of
non-standard use can dramatically shorten the life of the
frame and components. An y one or a combination of these
conditions may result in an unpredictable failure
.
All aspects of use being identical, lightweight bicycles
and their components will usually have a shorter life
than heavier bicycles and their components. In selecting
a lightweight bicycle or components you are making a
tradeoff , fav oring the higher performance that comes with
lighter weight over longevity . So, If y ou choose light-
weight, high performance equipment, be sure to have it
inspected frequently .
Y ou should have your bicycle and its components checked
periodically by your dealer for indicators of stress and/or
potential failure, including cracks, deformation, corrosion,
paint peeling, dents, and any other indicators of potential
problems, inappropriate use or abuse. These are important
safety checks and very important to help prevent acci-
dents, bodily injury to the rider and shortened product life
.
bicycles, steel has been largely replaced by aluminum
and some titanium. The main factor driving this change is
interest by cycling enthusiasts in lighter bicycles.
Properties of Metals
Please understand that there is no simple statement that
can be made that characteriz es the use of different met-
als for bicycles. What is true is how the metal chosen is
applied is much more important than the material alone.
One must look at the way the bik e is designed, tested,
manufactured, supported along with the characteristics of
the metal rather than seeking a simplistic answer .
Metals vary widely in their resistance to corrosion. Steel
must be protected or rust will attack it. Aluminum and
Titanium quickly develop an oxide lm that protects the
metal from further corrosion. Both are therefore quite
resistant to corrosion. Aluminum is not perfectly corro-
sion resistant, and particular care must be used where it
contacts other metals and galvanic corrosion can occur .
Metals are comparativ ely ductile. Ductile means bending,
buckling and stretching before breaking. Generally speaking,
of the common bicycle fr ame building materials steel is the
most ductile, titanium less ductile, followed by aluminum
.
Metals vary in density . Density is weight per unit of mate-
rial. Steel weighs 7.8 grams/cm3 (gr ams per cubic cen-
timeter), titanium 4.5 grams/cm3, aluminum 2.75 gr ams/
cm3. Contrast these numbers with carbon ber composite
at 1.45 grams/cm3.
Metals are subject to fatigue. With enough cycles of use,
at high enough loads, metals will eventually develop
cracks that lead to failure. It is v ery important that you
read The basics of metal fatigue below .
Let’s sa y you hit a curb, ditch, rock, car , another cy clist or
other object. At any speed abo ve a fast walk, your body
will continue to move forw ard, momentum carrying you
over the front of the bik e. Y ou cannot and will not stay on
the bike, and what happens to the fr ame, fork and other
components is irrelevant to what happens to y our body .
What should you expect from your metal fr ame? It
depends on many complex factors, which is why we tell
you that crash worthiness cannot be a design criteria. With
that important note, we can tell you that if the impact is
hard enough the fork or frame ma y be bent or buckled. On
a steel bike, the steel fork may be sev erely bent and the
frame undamaged. Aluminum is less ductile than steel, but
you can expect the fork and fr ame to be bent or buckled.
Hit harder and the top tube may be broken in tension and
the down tube buckled. Hit harder and the top tube may
be broken, the down tube buckled and broken, lea ving the
head tube and fork separated from the main triangle.
When a metal bike cr ashes, you will usually see some evi-
dence of this ductility in bent, buckled or folded metal.
It is now common for the main frame to be made of metal
and the fork of carbon ber . See Section B, Understanding
composites below . The relative ductility of metals and
the lack of ductility of carbon ber means that in a crash
scenario you can expect some bending or bucking in the
metal but none in the carbon. Below some load the carbon
fork may be intact even though the fr ame is damaged.
Above some load the carbon fork will be completely brok en
.
The Basics of Metal Fatigue
Common sense tells us that nothing that is used lasts forever .
The more you use something, and the harder you use it, and
the worse the conditions you use it in, the shorter its life
.
F atigue is the term used to describe accumulated damage
to a part caused by repeated loading. T o cause fatigue
damage, the load the part receives must be great enough.