The midsole is the part that gives
the boot its' stiffness. Traditional layers
of leather stiffened with steel shanks or more
modern methods using injection moulded nylon
boards give boots greater or lesser stiffness.
A stiff boot is not always needed and can be
difficult to wear if you are not used to it.
The degrees of flex and torsion are essential
attributes of boots and the correct amount of
stiffness must be chosen for your required usage.
Part of the purpose of the midsole is in shock
absorbing using micro and polyurethane materials.
midsole with a layer of traditionally
tanned leather stiffened by a second layer
of nylon incorporating a steel shank offers
control of the torsional stability and
longitudinal flex of the sole unit. A
further layer of insulating fabric offers
a thermal barrier against cold. On the
midsoles intended for Goodyear construction
a rand around the outside edge makes it
possible to stitch the upper andmidsole
together, the torsional stability and
longitudinal flex is controlled by a carbon
The modern manufacturing
method uses a midsole made entirely in
Nylon reinforced by injecting steel shanks
which, depending upon their length offer
differential grades of torsional stability
and flex control. The nylon maintains
its integrity at very low temperatures.
Composite sheet materials
provide lightweight structural support
of the foot arch but can also be used
as a highly engineered stiffener or shank.
The most complex shape can be made out
of Graphite composites with thermoplastic
tecnology. They reduce the weight of a
typical mountain shoe by 10% Because graphite
composites are resilient, they absorb
impact, spring back to the original shape,
and maintain performance for the life
of the shoe.