• Welcome to engineeringclicks.com
  • wheel speed?

    Discussion in 'Calculations' started by jawnn, May 22, 2013.

    1. jawnn

      jawnn Well-Known Member

      Joined:
      Jan 2012
      Posts:
      60
      Likes Received:
      0
      Did I get this right?
      if not what is the way please write it as if using a calculator. I don't understand math.

      52 sprockets / 12 sprockets on the rear= 4.333 ratio? X 60rpm crank speed x (20†x pi=62.8inch circumference) = 16327.987 inch min. / 12 inch = 1360.6655ft/min. and then 5280/1360.6655 = only 3.88 mph???
       
    2.  
    3. Erich

      Erich Well-Known Member

      Joined:
      Feb 2012
      Posts:
      222
      Likes Received:
      2
      Your error is in the last conversion.

      Allways write out the units and make sure they cancel .

      What you did:
      5280 ft/mile/1360 ft/min Your units end up minutes/mile.

      1360 ft/min *1mile/5280ft* 60min/hr= 15.45 mi/hr
       
    4. jawnn

      jawnn Well-Known Member

      Joined:
      Jan 2012
      Posts:
      60
      Likes Received:
      0
      so it should read like this?

      52 sprockets / 12 sprockets on the rear= 4.333 ratio? X 60rpm crank speed x (20” x pi=62.8inch circumference) = 16327.987 inch min. / 12 inch = 1360.6655ft/min. and then 5280/1360.6655 x 60 =
       
    5. Erich

      Erich Well-Known Member

      Joined:
      Feb 2012
      Posts:
      222
      Likes Received:
      2
      NO.
      It should read EXACTLY like my last line.
       
    6. jawnn

      jawnn Well-Known Member

      Joined:
      Jan 2012
      Posts:
      60
      Likes Received:
      0
      52 sprockets / 12 sprockets on the rear= 4.333 ratio? X 60rpm crank speed x (20†x pi=62.8inch circumference) = 16327.987 inch min. / 12 inch = 1360.6655ft/min. x 5280ft x 60min/hr= 15.45 mi/hr
       

    Share This Page