User Guide

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structure of an aluminum bike can be quite
inexpensive. However, some bike designers
push so hard to produce a cheap aluminum
frame that they don’t really use the benefit’s
of aluminum. As we said before, the extra
work we do often makes more difference than
the material itself.
Are all aluminum alloys basically the
same?
While all aluminum alloys are basically the
same density, they do vary quite a bit in
other mechanical properties. There is some
variation in tensile strength, both yield (in
layman’s terms, bending strength) and ulti-
mate (think breaking strength). There are
variations in fatigue strength, ductility, and
even manufacturing properties. As an exam-
ple, some really strong aluminum alloys can-
not be welded.
Some of the highest strength aluminum
alloys, particularly in the 7000 series, have
low elongation, or toughness, or resistance
to crack propagation. This is important
for overall strength and fatigue resistance.
With alloys exhibiting higher toughness, less
material is needed to resist fatigue, and this
can result in a lighter bike. Like with any
bike frame material, good design and man-
ufacturing is much more important than a
small difference in a single mechanical prop-
erty.
To further confuse the issue, some alloys
depend on heat treatment to attain their
strength after welding. A good heat treat-
ment can make a given alloy incredibly
strong. An inferior heat treatment can leave
the same alloy soft, weak, and prone to
breaking. As an example, with our propri-
etary heat treatment, the 6061 aluminum
in our Gold series alloy tests out to have
a higher tensile strength than considered
‘normal’ for 6061 alloy.
In addition to our own heat treatment,
we have also developed our own proprietary
alloy, ZR9000. This alloy has greatly
increased fatigue resistance, thanks to a spe-
cial mix of elements within the alloy. As
stated earlier, aluminum bike frames need to
be correctly designed to limit fatigue and yet
yield low frame weight and good ride quality.
With ZR9000’s extra fatigue strength, we can
make lighter, better riding structures and at
the same time actually increase the fatigue
strength of the frame.
What do the numbers mean?
When we discuss aluminum alloys, we refer
to a four-digit number. This is the alloy
name, based on the alloying elements in
the aluminum. A metallurgy reference would
explain precisely what elements are added
to the aluminum in a specific percentage
(assuming the material is of high quality; like
a bad chef, not everyone follows the recipe).
The second part of describing an alumi-
num alloy is the heat treatment or other
strength enhancements which have been
applied to the alloy. This is usually a letter
and number following the alloy name, like
6061 T6. With some alloys, special heat
treatments or work hardening are essential
to achieve their maximum strength. Other
aluminum alloys attain their maximum
strength by simply cooling at room tempera-
ture, also known as ‘normalizing’.
Since heat treatment adds extra steps to
manufacturing, it adds cost, as does an oven
large enough to handle bike frames. ZR9000
and 6061 aluminum require heat treatment.
7005 is usually normalized. Once again, heat
treatment is a process that requires quality
control. We use special ovens designed just
for heat treating bicycles. Our proprietary
design ensures that the heat treatment ‘reci-
pe’ is exact and repeatable to a very high
degree. The result is strong, lighter, better
riding bikes. One ride will show you how well
our bikes ride, our Limited Lifetime warranty
tells you that we have total confidence in the
manufacturing quality.