 Sales reached 4 million units per year for the first time.At the height of the boom, in 1972, 1973, and 1974, more bicycles than automobiles were sold in the U.S.

Additional factors contributing to the U.S. bike boom included affordable and versatile 10-speed derailleur-geared racing bicycles becoming widely available, the arrival of many post-World War II baby boomers at adulthood and demanding inexpensive transportation for recreation and exercise, and increasing interest in reducing pollution.The 1973 oil crisis, which increased the cost of driving an automobile, making bicycle commuting a more attractive option, is commonly assumed to have propelled the bike boom, but in fact, bicycle sales had already peaked when the crisis struck in October, 1973.