Why I don't trust mechanical speedometers.

Discussion in 'Motorized Bicycle General Discussion' started by Finfan, Jul 16, 2009.

  1. Russell

    Russell Active Member

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    Yes I keep my little digital speedometer running right next to my analog cheepo. However I doubt that either will ever see thousands of miles.
     
  2. roxrcool

    roxrcool New Member

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    I have one of the schwinn 10 dollar ones from wally world. you calibrate the wheel size when you
    first put in the battery. I used old tire tubes on the mount to lessen vibration, just like my motor mounts. vibration hasn't killed it (yet), and it is definitely accurate according to the speed trap thingeys on the side of the road as well as my little ladies car.
     
  3. tsmra

    tsmra New Member

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    I got one of the Schwinn digital speedometers tonight and what a pita to set up. You have to set the wheel factor, chose MPH or KpH and set the clock all in secession with out mistake or you have to reset the entire unit and start over. This one has a sticky left button causing it to jump 2 selection at a time every once and a while. By the way if you want to rest the unit just hold down both buttons for a second or 2 in stead of removing the battery.
     
  4. roxrcool

    roxrcool New Member

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    O.M.G....dance1you didn't build your own bike, did ya.....the speedo takes literally a minute to set up and another if you don't do it right the first time. the wheel factor is right in the little pamphlet in the kit. lmfao
     
  5. Hauzer

    Hauzer New Member

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    I have one of those, it's a great product. But if the button is sticking, you should just return it to the store for another one.
     
  6. tsmra

    tsmra New Member

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    laff Build my own? Not yet, motor is in the mail. It might only take a minute to set up if it worked correctly. The sticking button would make it skip digits or advance to the next screen. Yep they give you a wheel factor chart, handy. Just relating that I got a bad one.
     
  7. Russell

    Russell Active Member

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    The digital unit that I have sounds quite similar. I had to put a ferrite bead on the wire coming from the sensor. It was going crazy because of the electrical noise generated from ith ignition system. It seems solid now. When I said that I doubted that My analog and digital units would never see thousands of miles. It was the bike and moter that I doubted not the insturments. I'll be quite satisfied if I can get 800 or so Mi. of this cheap little motor. However with just 200 mi. it is performing well.
     

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  8. Mike Hunt

    Mike Hunt New Member

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    does anyone have a correction factor for the analog taiwan speedo that is advertised as suitable with 26"/27" wheels when using the 26 inch wheels? lets say according to the instrument im going 60km/h how fast am i really going?
     
    #28 Mike Hunt, Sep 7, 2009
    Last edited: Sep 7, 2009
  9. roxrcool

    roxrcool New Member

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    google has a really cool conversion thing. all you do is type in 60 kph in mph.....and you get

    60 kph = 37.2822715 mph
     
  10. Mike Hunt

    Mike Hunt New Member

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    the conversion is easy enough and i prefer metric anyway. what i mean is what is correction factor between the speed displayed on the speedometer vs actual speed? if theyre designed to be used with both 26" and 27", then its gotta be calibrated somewhere in the middle. on a 26" tire displayed speed would be a little faster than actual speed, while on a 27" tire displayed speed is a little slower than actual speed. i want to know how much its off
     
  11. azbill

    azbill Active Member

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    I think it is because a 26" is a mountain/cruiser tire and 27 is a skinny road tire...very close in circumference/height

    just like a 24x3 is very close to a 26x2.125 in height
     
  12. Mike Hunt

    Mike Hunt New Member

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    thats assuming the rotations per minute are accurate.
     
  13. xlite

    xlite New Member

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    I use 191 for the digital for both 26" and 27" which are actually same size. Dead on compared with GPS.

    These are very reliable once you take care of the reset problem and incredibly easy to set up. Only takes a few seconds. Calibration is also trivial assuming you have a cheap GPS (who doesn't these days?).
     
  14. LS614

    LS614 New Member

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    I won't put my money on it because I only just ordered it, but for those who want a classic look, why not go to the whizzer motorbikes catalog and buy one of their mechanical speedos. As opposed to those really cheap ones on ebay and spooky tooth, this speedo is made for the 26" whizzer wheel and I have never read any complaints about them. I am excited to get mine! After shipping it came to about $33. Just a suggestion
     
  15. BarelyAWake

    BarelyAWake New Member

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    I hear the Wizzer speedometers are a viable option, that they're at least designed for these speeds... but I dunno about calibration, accuracy & wheel/tire sizes *shrug*

    Good tip LS614 :D
     
  16. wildemere

    wildemere New Member

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    A table of circumference I have in a spreadsheet-

    Tire Size- mm- ft

    16x 1 3/8 1282 4.20602406
    20x 1.75 1491 4.89171753
    24x 1 1753 5.75129499
    26 x 1.0 1913 6.27622779
    26x 1.0 1952 6.40418016
    26 x 1.75 1985 6.51244755
    26 x 1.75 2023 6.63711909
    26x 1.9 2050 6.7257015
    26x 2.0 2055 6.74210565
    26x 2.1 2068 6.78475644
    26x 2.125 2070 6.7913181
    26x 2.35 2083 6.83396889
    700x20c 2086 6.84381138
    700x23c 2096 6.87661968
    700x25c 2105 6.90614715
    700x28c 2136 7.00785288
    27 x 1 2145 7.03738035
    700x32c 2155 7.07018865
    27x 1 1/8 2155 7.07018865
    27x 1 1/4 2161 7.08987363
    700x35c 2168 7.11283944
    27x 1 3/8 2169 7.11612027
    700x38c 2180 7.1522094
     

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