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I was out riding the super slab (I-75) yesterday and had cruise control set, according to the speedometer I was cruising at 77 MPH yet the GPS indicated I was only doing 74 MPH. I have read and understand the slight variances between the 2 due to electronic issues. But I have never read or heard being 3 MPH off. Is it normal for a GTL to be out of calibration on its speed sensor?
yes
 

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I was out riding the super slab (I-75) yesterday and had cruise control set, according to the speedometer I was cruising at 77 MPH yet the GPS indicated I was only doing 74 MPH. I have read and understand the slight variances between the 2 due to electronic issues. But I have never read or heard being 3 MPH off. Is it normal for a GTL to be out of calibration on its speed sensor?
My 2015GTL speedo and GPS read exactly the same. My 2001 K1200LT was 5 off.
 

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I was out riding the super slab (I-75) yesterday and had cruise control set, according to the speedometer I was cruising at 77 MPH yet the GPS indicated I was only doing 74 MPH. I have read and understand the slight variances between the 2 due to electronic issues. But I have never read or heard being 3 MPH off. Is it normal for a GTL to be out of calibration on its speed sensor?
To my understanding all speedos are calibrated 3-5% above actual speed. This occurs in cars as well as bikes. It is to ensure a safety margin and prevent under reading. My bike reads 105 kph when the GPS on the Nav 6 or on the "Speedometer" app on my phone read 100 kph. The frustrating thing is when I am sitting on 105 kph and the slow guy in the fast lane is only doing 100 kph :ROFLMAO:
 

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I was out riding the super slab (I-75) yesterday and had cruise control set, according to the speedometer I was cruising at 77 MPH yet the GPS indicated I was only doing 74 MPH. I have read and understand the slight variances between the 2 due to electronic issues. But I have never read or heard being 3 MPH off. Is it normal for a GTL to be out of calibration on its speed sensor?
Same. Never really noticed at slower limits but, yeah, it's off by about 3-4 MPH as you approach the sound barrier.
 

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I was out riding the super slab (I-75) yesterday and had cruise control set, according to the speedometer I was cruising at 77 MPH yet the GPS indicated I was only doing 74 MPH. I have read and understand the slight variances between the 2 due to electronic issues. But I have never read or heard being 3 MPH off. Is it normal for a GTL to be out of calibration on its speed sensor?
If your speedometer vs GPS is only 3 MPH difference at that speed, assume you are lucky and got a K1600 with minimal speedo error.
 

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If your speedometer vs GPS is only 3 MPH difference at that speed, assume you are lucky and got a K1600 with minimal speedo error.
Huh, I think they're universally off by 3 MPH...both of mine have been exactly that off whether at 30 MPH, 55 MPH, or 80 MPH. I don't think they're off by a fixed percentage but are actually off by a specific offset of 3 MPH.
 

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I was out riding the super slab (I-75) yesterday and had cruise control set, according to the speedometer I was cruising at 77 MPH yet the GPS indicated I was only doing 74 MPH. I have read and understand the slight variances between the 2 due to electronic issues. But I have never read or heard being 3 MPH off. Is it normal for a GTL to be out of calibration on its speed sensor?
Vehicle speed is a mechanical read out, meaning the speedometers are calibrated based on several vehicle characteristics, primarily tire / wheel diameter plus regulated safety tolerances. Any changes like tire sizes and wear will change speed readings, plus all manufacturers calibrate vehicle speedometers higher than actual speed due to regulatory requirements to ensure speed readings are never lower than the actual speed of the vehicle.
A GPS doesn’t measure speed, it measures position, then calculates vehicle speed mathematically based on position changes, which is more accurate than mechanical measurements. Plus a GPS doesn’t include regulatory tolerances mandated by the Government so it’s more accurate. However, GPS speed accuracy can change based on terrain. Flat straight roads generally allow better calculated speed accuracy than hilly, curvey roads. Even so, the GPS is generally more accurate than a vehicle speedometer.
 

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It gets even more interesting. on my '18 GTL with the average speed display.

Both the analog and digital speedos are off of the GPS speed by a few mph... BUT if on a straight and flat road I set the cruise to 75 mph (per the GPS) and reset the average speed display, both the analog and digital speedos will show ~79mph but the average speed display will lock exactly on what the GPS is indicating. This tells me that somewhere in there the system knows exactly how fast you are going but it intentionally display incorrect data on the two primary 'current speed' indications.
 
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GPS isn't amazingly accurate, well coded SatNav software predicts that you are staying on the same road unless your route takes you off it. Thats why at intersections sometimes the SatNav takes a few seconds to work out you have taken a slip road
One of the very first "features" I disable on any GPS I am using.
 

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It gets even more interesting. on my '18 GTL with the average speed display.

Both the analog and digital speedos are off of the GPS speed by a few mph... BUT if on a straight and flat road I set the cruise to 75 mph (per the GPS) and reset the average speed display, both the analog and digital speedos will show ~79mph but the average speed display will lock exactly on what the GPS is indicating. This tells me that somewhere in there the system knows exactly how fast you are going but it intentionally display incorrect data on the two primary 'current speed' indications.
Above some speed, I believe that is exactly a 3 MPH addition (probably 5kph converted to miles and rounded), not a percentage.
 

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Above some speed, I believe that is exactly a 3 MPH addition (probably 5kph converted to miles and rounded), not a percentage.
The point was, it has the capability of displaying the correct speed, if it "wanted" to... This is why I do not even display the digital speedo and ignore the analog one entirely. I go by what is displayed on my 476 mounted on the handlebars. I tried using the NAV IV speed display, but once it turns red, I cannot read the numbers. 👹 I use that only as a binary indicator of having reached the posted limit.
 
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The point was, it has the capability of displaying the correct speed, if it "wanted" to... This is why I do not even display the digital speedo and ignore the analog one entirely. I go by what is displayed on my 476 mounted on the handlebars. I tried using the NAV IV speed display, but once it turns red, I cannot read the numbers. 👹 I use that only as a binary indicator of having reached the posted limit.
I do exactly the same, for somewhat different reasons. I can't read the analog dial, at all. I almost always have music playing so the bike's digital speedo is inaccessible. Thus, I use the Nav VI GPS speed almost 100% of the time.

I too have mine set on a dashboard that turns red at what it thinks is the speed limit but I have no issue reading that. Do you have colorblindness??? If you can't see it once it turns red, perhaps you need to select a different dashboard (assuming the Nav IV allows that) with a different background so that the red stands out?
 

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I do exactly the same, for somewhat different reasons. I can't read the analog dial, at all. I almost always have music playing so the bike's digital speedo is inaccessible. Thus, I use the Nav VI GPS speed almost 100% of the time.

I too have mine set on a dashboard that turns red at what it thinks is the speed limit but I have no issue reading that. Do you have colorblindness??? If you can't see it once it turns red, perhaps you need to select a different dashboard (assuming the Nav IV allows that) with a different background so that the red stands out?
Nope. Not colorblind. Just eyes that are getting old. 😕

During the day I can see the numbers, I just cannot make out what they say. Just a red blob. At night it gets better and I can usually make out what they say. Better contrast between the numbers and the "night" screen. This is with the map view and the current speed/posted speed in the corner of the screen.

The 476 is mounted in the middle of the bars on a RAM mount and is much closer with larger numbers so it is much easier to see.
 

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This is with the map view and the current speed/posted speed in the corner of the screen.
My Nav VI has about a dozen map views....different "dashbords" with the layout of the data being different. The size of the numbers vary between the different options. I'm not sure if the Nav IV had the option of multiple dashboards, but if it does, are you using the one with the biggest numbers?
 
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