All Mountain Bike Parts Descriptions
#10) Wheel Rims - Also known as HOOPS, they hold the tires and tubes
to the wheel.
Rims provide shock absorption as well,
by buckling during an impact and then popping back
into shape from the spokes tension holding its shape
together. They were made of wood, then steel, but
now aluminum because of its flexible nature and its
lightness. The number of spoke holes in a rim vary,
depending on the bikes intended use. Road
bikes use less spokes which make the wheel weaker,
but using less spokes also cut through the wind better.
BMX bikes use 48 hole rims, 48 spokes. Thirty-two
holes rims seem to be the standard for most mountain
bikes, a good low drag but maximum strength combination.
Aerodynamic shaped rims help smooth out the air flow,
although I find that they crack easier from big impacts
because they don't flex the same way a regular rim
might. It would be best to keep them on the road bikes.
Bike Parts Diagram