Course Work: MSE 480 Materials Dissection
The Object: A Bicycle Brake Pad
The object that I have chosen to dissect is a bicycle rim brake pad. A deceptively simple object, the brake pad undergoes tremendous stresses while working to slow down a cyclist. A brake must withstand continual wear, as well as compressive and shear. This makes for a very interesting object to inspect with many aspects affecting its design and the material from which it is ultimately made. Pictured here is a Shimano 105 caliper style road brake pad.
The function of the brake pad is very simple. By pressing perpendicular to the braking surface of the rim, friction is created between the stationary pad, and the rotating wheel.
This friction causes the rotating wheel to slow, or come to a complete stop. By drawing a free body diagram of the brake pad under use,
we see that it is subjected to a shear loading down the long axis of the pad, as well as a compressive force perpendicular to the braking surface. By the very nature of the way in which the brake operates, by friction, we see that the brake pad will be subjected to abrasive wearing forces as well.
Next: Current Materials
all pictures by Paul Miska
this site last updated 9-28-2002 by pmiska@deepthought.org