I need help in figuring out the ratio on motor speed versus gear ratio versus tire size

Discussion in 'Science and Technology' started by Daryl Hunt, Mar 17, 2018.

  1. Daryl Hunt
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    Daryl Hunt Gold Member

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    I am working on a new project. I have been using in hub motors. I want to use a chain driven motor instead. Here is the problem.

    The speed of the external motors are 4800 rpm
    The available motor drive gears are from 9 to 13 teeth
    The available shaft drive gears are from 32 to 89 teeth
    The size of the Wheel (OD) is about 20 inch.

    I am trying to keep the road speed down to no more than 37 mph. Is this possible in this range? Or am I going to blow well past that no matter what ratio I choose. My math isn't that good anymore.
     
  2. Rambunctious
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    Rambunctious Gold Member

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    Sprocket Ratio Calculations
     
  3. tyroneweaver
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    tyroneweaver Gold Member

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    Well. If a car has 4800 rpm and has 4:11 differential, what would be the road speed? 60??? Go from there.
     
  4. BULLDOG
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    BULLDOG Diamond Member

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    Try this.

    a= motor RPM
    b= drive gear teeth
    c= driven gear teeth
    d= wheel diameter

    MPH= (a(b/c) * (3.14*(d/2)*(d/2)))/ 60/5280
     
  5. Daryl Hunt
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    Daryl Hunt Gold Member

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    I came up with a motor sprocket of 8 teeth with an axle socket of 54 on a 20 in wheel at 4800 rpm at 35 mph. Please check my figure.
     

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