leather has the advantage in abrasion resistance. No problems up to 90 degrees.
Abrasion resistance is important, possibly more important than
protecting against impact - low siding off the bike only drops you
from about a metre anyway... There are a few different types of
material that you can wear:
* Leather
Leather is still the king. Has been for years and is unlikely to lose
the crown in a hurry. Lorica (an artificial leather), as used on
mostly Italian boots, is not very good at all. Leather breathes,
abrades slowly (depending on type) and is more or less showerproof.
Great against the wind, but is hot in summer. Can be dyed to almost
any colour, and there are a number of places around that make to
measure. And it never seems to wear out (except against a road) - old
jackets are just as good as new ones.
* Kevlar
Close weave kevlar is effective but doesn't slow you down (the world
is waiting for a kevlar suit with little moulded rubber lumps on it
for braking). Unfortunately, most of the kevlar used in protective
clothing is loose or open- weave type. This is not much good because
the first impact with the ground destroys the weave of the kevlar and
there is little left to protect the skin. If there are two layers then
the performance is much better because the first layer protects the
second layer which does the sliding.
* Waxed Cotton
Good for sliding on once, possibly more. Warmer than leather and more
waterproof, but gets dirty when hot. Can leave stains on other
clothes. (more detail needed)
* Nylon/Cordura
OK for strength, but the weave in the nylon can snag on rough surfaces
and tear. Is waterproof, but doesn't breathe. Good for winter,
Dri-Riders are made from this. A good range of colours too.
* Denim
Not really a protective material. If you fall at 60km/h, denim should
protect you for about 1.3m, after that you're on your
own. Interestingly enough, older jeans are better (as long as they
have no holes) because their material is smoother and slides better.
Jeans with 'fashionable' holes in the knees are no protection at all,
and if you fall off with these on you'll get no sympathy from me.
