Unfortunately, in a cable’s life there will be a time where it experiences fatigue. Sometimes the fatigue will be caused by harsh environmental conditions. Salt water, acids, and other harsh elements will commonly reduce your cable life expectancy. However, there is another reason that your cable may be not lasting as long as you would hope…pulleys and sheaves! Pulleys and sheaves play a significant role in the lifespan of cable. One specific engineering concept, called the D:d ratio, helps extend this cycle life by matching the ideal pulley diameter to a corresponding cable diameter. Here is a closer look at how the D:d ratio functions.