Speed calculator

Discussion in 'Motorized Bicycle General Discussion' started by big-e, Jan 21, 2011.

  1. big-e

    big-e New Member

    Joined:
    Jan 21, 2011
    Messages:
    16
    Likes Received:
    0
  2. corgi1

    corgi1 New Member

    Joined:
    Aug 13, 2009
    Messages:
    2,282
    Likes Received:
    2
    I am thinking when entering the motor rpm that what we are really using is the clutch sproket rpm which is about 1/4 the motor rpm???
    and if 6000-7000 is about safe high motor rpm ,then the sproket rpm is 1500-1700 rpm to enter into the calculator (this seemed to make the mph come out like I hear on the threads all the time)
    I am talking about a china girl
     
  3. solokumba

    solokumba New Member

    Joined:
    Nov 24, 2010
    Messages:
    215
    Likes Received:
    0
    I think I'm doing it wrong.
    No one said there would be math.
     
  4. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

    Joined:
    Mar 20, 2008
    Messages:
    6,192
    Likes Received:
    19
    Those speed calculators are great when you have a powerfull engine... unfortunately, our little china engines just don't have the power to push bicycles much past 40MPH.
    I can't tell you how many times I've read guys saying "with this sprocket, my bike will go 57 MPH..." & then they only find out that their bike only goes slower with that small sprocket. :(
    There are several guys here who have really fast bikes; but their engines are heavily modified.
     
  5. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,641
    Likes Received:
    62

    LOL Solo! I am right there with ya
     
    #5 Dan, Jan 22, 2011
    Last edited: Jan 22, 2011
  6. Bob Gurkin

    Bob Gurkin New Member

    Joined:
    Jan 1, 2011
    Messages:
    53
    Likes Received:
    0
    I used to think I wanted to go fast on a bicycle until a friend wrecked his at 25mph. A month in the hospital and I doubt that he will ever be 100%
     
  7. Comrade Alfonzo

    Comrade Alfonzo New Member

    Joined:
    Jul 15, 2009
    Messages:
    143
    Likes Received:
    0
    Weeell, I put in 6500 for clutch sprocket rpm, I wish my bike was that awesome.
     
  8. corgi1

    corgi1 New Member

    Joined:
    Aug 13, 2009
    Messages:
    2,282
    Likes Received:
    2
    114 is pretty quick
     
  9. big-e

    big-e New Member

    Joined:
    Jan 21, 2011
    Messages:
    16
    Likes Received:
    0
    i dont have anything specific to a bike motor.My motor is from a almost new 42cc poulan chainsaw. Unfortuanantly i have a 20 tooth clutch sprocket and a 40 tooth drive sprocket. ill put up pics when i get them. Expect my bike to look like a motorcycle. No pedals here and a long chopped fork with ape hangers on it too. imturniong my front triangle into the gas tank. like i said ill post pics wheni get things done to the bike.
     
  10. big-e

    big-e New Member

    Joined:
    Jan 21, 2011
    Messages:
    16
    Likes Received:
    0
    i got alot done but havent been taking pictures
    once i get in the groove i only stop long enough to grab a beer and then back to it
     
  11. Kristof

    Kristof New Member

    Joined:
    Jan 21, 2011
    Messages:
    232
    Likes Received:
    0
    I am facing a dilemma. I have a direct drive clutch (10T) to a 36T axle sprocket with a 26 inch diameter wheel. The calculator says that at 2000 RPM (when clutch engages) I'll be going at 43 mph. I may have a bad setup. My engine does not have built in gear reduction.

    I've read that people are switching over to 36T sprocket, so I bought one, but those people had those little 50cc engines with built in gear reduction. Now I don't know what to do, I've spent $80 on parts already.
     

Share This Page