// MANUAL
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 compo-
nents you are making a tradeoff, favoring the higher performance that comes with lighter
weight over longevity. So, If you choose lightweight, high performance equipment, be sure
to have it inspected frequently. You should have your bicycle and its components checked
periodically by a bicycle 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 import-
ant to help prevent accidents, bodily injury to the rider and shortened product life.
2. Perspective
Today’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. We discuss some of the trade-offs made in designing your bicycle
and what you can expect from your bicycle; and we provide important, basic guidelines
on how to maintain and inspect it. We cannot teach you everything you need to know to
properly inspect and service your bicycle; and that is why we repeatedly urge you to take
your bicycle to a bicycle dealer for professional care and attention.
WARNING: Like any mechanical device, a bicycle and its components are subject
to wear and stress. Different materials and mechanisms wear or fatigue from stress at
different rates and have different life cycles. If a component’s life cycle is exceeded, the
component can suddenly and catastrophically fail, causing serious injury or death to the
rider. Scratches, cracks, fraying and discoloration are signs of stress-caused fatigue
and indicate that a part is at the end of its useful life and needs to be replaced. While the
materials and workmanship of your bicycle or of individual components may be covered
by a warranty for a specied period of time by the manufacturer, this is no guarantee that
the product will last the term of the warranty. Product life is often related to the kind of
riding you do and to the treatment to which you submit the bicycle. The bicycle’s warranty
is not meant to suggest that the bicycle cannot be broken or will last forever. It only means
that the bicycle is covered subject to the terms of the warranty. Please be sure to read
Appendix B, Intended Use of your bicycle and Appendix C, the lifespan of your bike and its
components.
A. UNDERSTANDING METALS
Steel is the traditional material for building bicycle frames. It has good characteristics, but in
high performance 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 characterizes the
use of different metals 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 bike 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 corrosion resistant, and particular care must be used where it contacts other metals
and galvanic corrosion can occur. Metals are comparatively ductile. Ductile means bending,
buckling and stretching before breaking. Generally speaking, of the common bicycle frame
building materials steel is the most ductile, titanium less ductile, followed by aluminum. Metals
vary in density. Density is weight per unit of material. Steel weighs 7.8 grams/cm3 (grams
per cubic centimeter), titanium 4.5 grams/cm3, aluminum 2.75 grams/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
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