Speedometer is way off

Discussion in 'Other Service and Maintenance' started by robermv32, Aug 21, 2014.

  1. robermv32

    robermv32 Active Member

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    2014 FLHTCU 6000 miles. I'm a retired police officer and was cruising down the road just enjoying my life. The new bike is running like a champ and the day is just beautiful. When suddenly up ahead, coming at me is a cop car. A quick check of the speedometer and YIKESSS it says I'm doing 70 mph. Too late to try to slow down....but what's this ? The officer just passes right by. No brake lights. He's not coming. What ?? ?? So, I start to wonder. I have a Garmin GPS from my trade in and I installed it on the ElectraGlide. At 30 mph we match, but as the speed increases there is a difference between GPS and Bike. Bike says 60 GPS reads steady 54 Bike reads 65 GPS 61, Bike 70 GPS 65. The faster I go the greater the difference. So, I go find my cop buddy and ask him to verify with the radar. The GPS is right. The Bike is off. Any suggestions ? Anyone else ever check their bike ? I now go by the Garmin.
     
  2. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    Mine is off as well but mine reads slower than I'm actually going. Harley's are notorious for speedometers not reading correctly.
     
  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    It is not unusual for a speedometer to read lower than actual speed there is a permissible variation of up to 10% for all vehicles but only to show a higher speed than the vehicle is travelling
    A speedometer is not permitted to show less than actual speed
    As the tyre wears then the speedometer will have a greater discrepancy from actual speed
    With new tyres I would expect actual speed at an indicated 60mph to be around 57 or 58 mph and with worn tyres to be around 55 or 56

    Brian
     
  4. Breeze3at

    Breeze3at Well-Known Member

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    My '07 FLHTC is off by just about the same amount as yours. I prefer using the GPS speed because it turns red when I'm exceeding limit. I don't have to remember the posted speeds. Your bike is new, but you will probably notice a larger disparity as the R. tire wears and gets smaller.
     
  5. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    I always see blue ligths when mine exceeds the limit! :D

    Sorry, I couldn't help it.......
     
  6. 03HD883R

    03HD883R Active Member

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    I never noticed this. I've been wanting to get a GPS mount for my bike, but just haven't gotten around to it. Next time I'm out and about, I'm going to Velcro my GPS to my handle bar so I can check it's speed.

    I wonder how accurate this makes the odometer reading.
     
  7. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    It will most definitely affect how many miles you put on but think of it on the bright side, when you sell it you can tell the buyer it really has less miles on it.:newsmile100:
     
  8. dbmg

    dbmg Experienced Member

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    Nothing to worry about. Cars have the same problem. That's why the police cars have certified speedometer that are checked for calibration on a regular interval. I would not even waste the energy. Just sit back and relax and enjoy the miles covered on that 2014....:s And remember your gas gauge is just as inaccurate also......
     
  9. 03HD883R

    03HD883R Active Member

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    I guess as long as it doesn't say you are doing 55 mph and you are really doing 65 mph, you are good.

    It's just interesting.
     
  10. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    A good way to check if one doesn't have a gps unit is find one of the speed radar signs and check your speed against it's reading. I seem to see them all over the place.