Please more info on Mikes "Sweet 5 to 1 chain drive"?

Discussion in 'Rack Mounted Engines' started by Little Thumper, Mar 17, 2012.

  1. Little Thumper

    Little Thumper New Member

    Hey Mike.....Can you tell use more about your set up...What gear ratio? How does it climb? What is the top speed??...Thanks

    I tried posting on your thread and it wont let me??:ack2:

  2. Mike St

    Mike St Member

    The top speed depends on your sprocket ratio. There's two drive sprockets, 11t and 14t, and how fast you go depends on the size of your wheel sprocket. I set my speed to 20-22 mph with a 11t drive sprocket, and a 54T rear wheel sprocket to be legal in Illinois, but very simply, and quickly, I can change out the 11t to 14t for 28-30mph. There's real flexibility in the design. If your're building my design, you must be careful to select the right thickness of aluminum parts, otherwise, the aluminum frame may collapse or bend under the torque of the motor. Most folks on these sites will never actually build an original frame. They depend on kits, but when you strike out on your own, there's some real strength engineering that has to be designed into the parts, normally using higher thickness aluminum, and in some places reinforcing with steel. It's not quite as simple as it looks.
  3. Little Thumper

    Little Thumper New Member

    Thanks Mike....Nice job!!...Btw...I Build my own..Heres a bike thats almost done.

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  4. Mike St

    Mike St Member

    Cool! Shows a lot of original design.
  5. Little Thumper

    Little Thumper New Member

    Thanks...The V drive roller works well for high hp motors in dry weather only...The bike is geared for 55 plus!!...:eek:

    Back too your cool design...How is the drive sprocket attached to the wheel ??
  6. Mike St

    Mike St Member

    The drive sprocket is on the gearbox. For complete directions to all the parts required and their order, refer to Treewks postings on this site. He gives all the info on the double right-sided drive. It's just a few parts.
  7. Little Thumper

    Little Thumper New Member

    Yes...Your right..Can you please give us more info on how the wheel sprocket is attached?
  8. Mike St

    Mike St Member

  9. loquin

    loquin Active Member

    re your drive roller:

    I like the FD setup you have, except for one thing: Your 'V' roller does give more roller-to-tire contact by 'wrapping' around the tire surface... but it also has greater losses, roller wear and tire wear between roller and tire than a single diameter roller.

    At the larger roller diameter, the speed at a point on the circumference of the roller is moving faster than a point at the smaller diameter. (the linear speed is proportional the diameter times the RPM, and since, at a given RPM, the RPM times the smaller diameter gives you a slower speed than the RPM times the larger diameter.) Something has to slip, which leads to increased tire and roller wear, increased losses at the roller-tire interface, and hotter tires.

    If there were a 10% greater diameter (large diameter/small diameter = 1.1) then, for every revolution of the drive roller, a point at the large diameter will 'move' 10 percent further than a point on the smaller diameter. Since the roller can only spin at one RPM, and the tire can only spin at one RPM... there HAS to be 'slip' in the system.

    And, since the large diameter of the roller contacts a smaller diameter portion of the tire, the effect is actually a little worse than the 10% I mentioned. (the percentage is much less - a quarter inch when compared to the drive roller is much more than a quarter inch when compared to the wheel diameter.)

    Here's an estimate, based on what I can see of your setup : You've got a high RPM motor. I'll go on the assumption that it has a 10000 max RPM. Since you say that it's geared for 50 MPH, this means that the roller diameter is about 1.75 inches; I'll assume that this is the large diameter on the roller. And, it looks like the roller is about a quarter inch thinner in the middle.

    So, based on these assumptions, at 10000 RPM, when the large diameter of the roller is moving at a calculated 'ground speed' of 52.06 MPH, the small diameter is moving at a calculated 'ground speed' of only 44.62 MPH. There IS slippage taking place where the rubber meets the roller - about seven-and-a-half MPH worth at top speed.

    Note that with a single-diameter roller, the tire deforms to a single roller diameter, so you don't have the same roller 'scrubbing' that you have with a multi-diameter roller. You WILL get a little, but, since it's based on the deformation of a 26 inch tire the amount if scrubbing is proportionally smaller... for a quarter inch deformation in a 26 inch tire, the percentage of slip caused by tire deformation is a little less than 1 percent, instead of apx. 14 percent in your case. (And, the V roller also has approximately the same tire deformation slip as a single-diameter roller.)
    Last edited: Mar 19, 2012
  10. Little Thumper

    Little Thumper New Member

    When I finish the expansion chamber and break it in...Ill give you a real world report!!:hurray:
    Last edited: Mar 19, 2012
  11. Little Thumper

    Little Thumper New Member

    Mikey..Where did you get the free wheel part's from???