As riders get older,
softer and more cashed up, more high tech fabrics are being used in boots,
gloves and jackets. The best known and
most expensive is Gore-tex which was developed for
mountaineers, bushwalkers and cross-country skiers. For these users it can reduce the risk of
hypothermia by allowing sweat to evaporate off preventing damp clothes in cold
weather.
Gore-tex
is a PTFE membrane with pores so fine that water vapour can pass through while
droplets of rain can’t. It is usually
sandwiched between a fabric outer and inner.
As it is expensive, other fabrics have come onto the market employing
coated fibres that absorb moisture and wick it to the outside surface. These are usually less efficient in how much
they can transmit and Gore-tex has retained its
premium image.
It does, however, have
limitations. It depends on the exterior
shell remaining repellent to droplets.
The moment the outside of the sandwich gets saturated breathability drops sharply. This can be restored on a hiking jacket by
washing and ironing it or spraying on proprietary treatments like Scotchgard. Another
problem is the membrane becoming clogged with body oils or dirt. Again, on a hiking jacket this can be washed
out. Finally, the transmission of vapour
depends on the pressure differential between a warm moist zone inside the
garment and a cooler drier one outside it.
In a warm humid climate, Gore-tex loses its
advantage.
In the case of leather
motorbike boots gloves and jackets, the Gore-tex
can’t be washed and over time becomes clogged.
In my experience it’s good for about a year and then you might as well
be wearing a plastic bag. With leather outers, leather conditioners tend to fill the pores so
reducing breathability as well, and if conditioners
are not used water take-up while riding in the rain has a similar effect. Treated fibre fabrics suffer from similar
limitations if teamed up with a leather shell.
Gore-tex
socks are available and that addresses the washing but not the shell-saturation
issue. The optimum application of
breathable waterproof textiles would be as removable liners within
water-repellent cordura shells.
Ern Reeders