User Guide

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LEMOND GEOMETRY
LeMond Geometry- A different perspective
LeMond geometry is different than many
of the bikes on the market today. There
are many explanations for this, some useful,
some not so well thought out. We’d like to
suggest a different perspective here.
What’s different about the geometry?
First, let’s talk about what the differences
are. There are several key points which
vary from some bikes on the market today.
The differences may be small, but when
combined the effect is definitely noticeable.
Understanding how they work will help you
understand the ‘feel’ and how it will benefit
your riding.
• Matched head tube angle and fork rake.
By carefully choosing a frame’s head tube
angle and matching it to a correct fork rake,
frames can have a low initial stability and
great final stability. This means you can have
a frame that turns easily, and then when
leaned over in a turn becomes increasingly
more stable.
Greg has said that when Pros are descend-
ing the Alps at 80kph, they need bikes that
hold a line well, not steering that is quick
and reactive. When descending fast, Pros use
every inch of road width. They aggressively
lay the bike into a corner knowing they can’t
change their line. With such a narrow margin
of error, it’s more important that a bike hold
the line than be quick turning. Greg’s geom-
etry adds stability, especially when combined
with other facets of the design.
• Slightly lower bottom bracket.
A lower bottom bracket lowers your body
on the bike, and your center of gravity. When
you are closer to the ground, the bike is
more stable and tracks straighter. It’s true
that this reduces pedal clearance, but at the
extreme cornering angles and high speeds of
a Pro road race the riders have their inside
pedal up in the corners anyway. To Greg,
feeling secure while eating or removing a
rain jacket is more useful than extreme pedal
clearance.
• Increased top tube length.
If you only look at top tube numbers,
Greg’s geometry may look really long.
However, under a more accurate analysis the
front/center is actually comparable to other
good road bikes. The difference is that the
seat tube is laid back. When the seat angle
is laid back, it’s normal for the top tube to
increase in length.
• Longer chainstays with shallower seat angle.
Like with the longer top tube, slightly lon-
ger chainstays are a result of a shallower seat
tube angle. This adds comfort and stability to
a bike. For a road racer, this allows them to
relax on the bike. If they expend less energy
throughout the entire race, they will have
more energy when the crunch comes. Shorter
chainstays may add stiffness to a bike during
a hard effort, but when sprinting for a stage
win Greg found that feeling fresh was more
useful than a stiff bike.
• Reduced seat angle.
Some say this is to accommodate a long
femur (thighbone), but good bike fit relies on
more than bone length; it also considers the
physics of riding.
Another theory is that pushing the saddle
rearward allows you to “pedal early”, or apply
pedal pressure earlier in the pedal rotation as
it goes from the top (12 o’clock) position.
While either of those theories may apply
in some cases, an analysis of biomechanics
indicates the primary benefit of the slack
seat angle is more powerful climbing through
hand opposition.
Examine the dynamics of a rider in the
saddle on a tough Tour climb, say something
10km long and in excess of a 10% grade.
When seated on the bike most climbers ride
with their hands on the top of the handle-
bars. This allows comfort and good breath-
ing. They don’t need to be in the drops,
because climbing speeds are low enough that
aerodynamics do not have much effect.
As the grade increases the pedal force
increases, assuming race pace at a constant
cadence. As pedal force increases, so do the
opposite forces lifting you off the saddle. The
force stabilizing a seated rider is partially
the friction created on the saddle by gravity,
partially the position of the hands relative
to the saddle. As pedal force increases, it
takes more force to stabilize your body. Since
gravity does not increase, it requires addi-
tional opposition from your hands to keep
your body quiet in the saddle. Rather than
move your hands (and handlebars) to oppose
your feet, the saddle is moved back so that
the bars are further away. This position