This file: http://user.it.uu.se/~embe8573/bike/bearings.txt


  How many bearings has a single speed bike,
  assuming an F&S Torpedo coaster brake hub?

  Answer:


    rear hub          3  [1]
    crank/BB          2
    pedals        2*2=4  [2]
    front wheel       2
    head tube     +   2  [3]
                  -----
                     13


  Bonus fact: The balls are sometimes loose,
  sometimes in a retainer, both in the rear and
  front wheel hubs.


[1] 2 big, 1 small. The 5-roller clutch is not
    a roller bearing.

[2] For cheap pedals: 2*1 = 2. Then the total
    is 11.

[3] Headset 1, fork 1.