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Thread: How Accurate is the Speedo?

  1. #1
    Registered User jamo's Avatar
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    How Accurate is the Speedo?

    When it says "100 mph," how fast am I really going?
    Turn on, tune in and ride off

  2. #2
    Debbie's Servant Lee's Avatar
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    Approx 97 mph.
    Lee
    2016 R1200RS
    MOA # 30878
    Past BMW Bikes: 2011 K1300S, 2003 K1200RS, 1991 K75S, 1987 K75T, 1984 R100RT

  3. #3
    Registered User jamo's Avatar
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    What? 97%! So when my speedo said 120 numerous times while I was passing a few cars on highway 14 between Richland Center and Lacrosse this weekend, I was actually doing only about115?

    Once last year, I deceived to pass that fifth car and gave it a go. As I passed the speedo on my Bandit was 114. I looked over and the car said “Sheriff” on the door. He stopped me and wondered where I’d come from, but didn’t ticket me. He wasn’t on traffic duty.
    Turn on, tune in and ride off

  4. #4
    Debbie's Servant Lee's Avatar
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    Seems to be a Europe thing to have the speedometers read high.
    The speedometer in our last 3 Chevys are spot on.
    Lee
    2016 R1200RS
    MOA # 30878
    Past BMW Bikes: 2011 K1300S, 2003 K1200RS, 1991 K75S, 1987 K75T, 1984 R100RT

  5. #5
    skibum69 skibum69's Avatar
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    All of my bikes and my Elements were between 5 & 8% low on the speedo, easiest way to tell is run with your GPS. My new to me Acura MDX is about 1-2%. It pays to know for certain.
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  6. #6
    Debbie's Servant Lee's Avatar
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    Quote Originally Posted by skibum69 View Post
    easiest way to tell is run with your GPS.
    Before GPS I used to time myself for 10 miles on a interstate.
    Lee
    2016 R1200RS
    MOA # 30878
    Past BMW Bikes: 2011 K1300S, 2003 K1200RS, 1991 K75S, 1987 K75T, 1984 R100RT

  7. #7
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    I can only speak for my R9T using a gps.
    Anywhere from 3 to 6 MPH fast.
    Seems the faster you go, the more optimistic it is.

  8. #8
    Registered User pappy35's Avatar
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    My Dodge Durango and Kia Optima are spot on. My RT reads 2mph faster than actual up to 70 mph and +3mph from 75 mph on.
    '13 R1200RT 90th Anniversary Edition

  9. #9
    SURVIVOR akbeemer's Avatar
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    An old document, but illustrative of BMWís approach to speedometer accuracy.

    BMW-SPEEDO-jpg-zpsxmxhbqzw.jpg
    Kevin
    The Outpost, Silver City, Montana
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    2018 Ural Gear Up, 2017 R1200GSA

  10. #10
    Quote Originally Posted by akbeemer View Post
    An old document, but illustrative of BMW’s approach to speedometer accuracy.

    BMW-SPEEDO-jpg-zpsxmxhbqzw.jpg
    When it comes to stupid that ranks right up there. The part labeled "Important Note" is as dumb as a box of rocks. It says, we know it is wrong and your GPS is right but use the speedometer anyway. Sheesh! The arrogance is astounding.
    Paul Glaves - "Big Bend", Texas U.S.A
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  11. #11
    Old and Tired Gillie Dog's Avatar
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    Quote Originally Posted by pappy35 View Post
    My Dodge Durango and Kia Optima are spot on. My RT reads 2mph faster than actual up to 70 mph and +3mph from 75 mph on.
    Yep.

    My Japanese, Italian and American made scooters were always right on even with new/different tires. But not my German one.

    Obviously the Germans are smarter than the Japanese, Italians or Americans.

    GD
    (New to me) 2010 R1200RT after HD Electra Glides for 35 years

  12. #12
    Registered User jamo's Avatar
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    Quote Originally Posted by Lee View Post
    Approx 97 mph.

    Lee, I donít know how you got three percent, whether you measured it with a gps, but to me it seems more like the ten percent mentioned in the document. I have to be going 80 on the super slab just to keep up.
    Turn on, tune in and ride off

  13. #13
    My 2016 RS reads 135 GPS says 127. But It is pretty much Wrong even at low speeds 60 on the Speedo is about 57.
    I hate the Display on this bike Speedo is the only thing readable above 60 and it is wrong. When I say readable I mean I am not going to look down long enough to get a view of the really important cues.
    Gator in Dallas

  14. #14
    Debbie's Servant Lee's Avatar
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    Quote Originally Posted by jamo View Post
    Lee, I donít know how you got three percent, whether you measured it with a gps, but to me it seems more like the ten percent mentioned in the document. I have to be going 80 on the super slab just to keep up.
    Can't remember at 100 but in the 75 to 80 mph range the speedometer reads 2.5 to 3 mph higher than the GPS.
    Lee
    2016 R1200RS
    MOA # 30878
    Past BMW Bikes: 2011 K1300S, 2003 K1200RS, 1991 K75S, 1987 K75T, 1984 R100RT

  15. #15
    Knight-Errant 1957mpd's Avatar
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    Deutscher Gerštefehler

    It's not just a BMW motorcycle thing; every BMW auto I've had displayed the same speedometer variance from GPS-determined speed.

    Mark
    "Solů el que ensaya lo absurdo es capaz de conquistar lo imposible." Miguel de Unamuno 1905

    Mark - Las Cruces, NM - '10 K1300S and '17 R1200 GSA

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