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HD speedometer accuracy

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Old Sep 7, 2006 | 04:53 PM
  #1  
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veniculum
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Default HD speedometer accuracy

I don't know if this has ever been covered, but I figured I'd ask anyway. I was just wondering how accurate your speedometers. My buddy and I were out for a ride a week or two ago, and he has a GPS on his honda. Both of us were riding at the same speed and both of our speedometers were reading 50 mph. At the same exact time, his GPS was saying we were doing 45.
I was just wondering if this was the case with all Harleys or if this was unique from bike to bike.
Thanks.

Todd
 
Old Sep 7, 2006 | 04:59 PM
  #2  
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Default RE: HD speedometer accuracy

Good question! I noticed that while going past one of those Speed Sensor signs it said I was doing 35, my speedo said 40.
 
Old Sep 7, 2006 | 05:03 PM
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Default RE: HD speedometer accuracy

I've done a lot of rides w/ my GPS and it is always right on (or at least +/- 1 mph, hard to tell with an analog speedo). Even at higher speeds it is VERY close.
 
Old Sep 7, 2006 | 05:17 PM
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Default RE: HD speedometer accuracy

I'll bet that the setting on his GPS was for nautical miles. That is the default on most GPS units. One nautical mile is about 6,076' which is about 1.15 miles.

I'm a surveyor and we're ALWAYS running into this stuff. Now try checking different coordinate systems and see how confused we can all get.

 
Old Sep 7, 2006 | 05:26 PM
  #5  
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Default RE: HD speedometer accuracy

My bagger speedo says "certified" at the bottom which if I recall means it is accurate for police use. Whether or not that is worth much, I don't know.
 
Old Sep 7, 2006 | 05:50 PM
  #6  
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Default RE: HD speedometer accuracy

I can tell you in about two weeks.
I will get a ticket for riding exactly 100 km/h on my speedometer where only 80 km/h was allowed.
The police flash-photographed me with verified and certified equipment.
The exact speed will be on the ticket.
Btw. this is the expensive way to check the accuracy of your speedometer.
 
Old Sep 7, 2006 | 06:00 PM
  #7  
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Default RE: HD speedometer accuracy

A few years ago, Cycle magazine (or Rider or one of those I used to take) used to post speedometer accuracy in their reviews (back when they did other things besides crotch rockets). The Harley speedometer was an indicated 60 mph @ an actual 60 mph.

I've noticed that if I do the speed limit, in an area where I expect the cagers to be doing the speed limit as well (like when there's a cop taking pictures on the side of the road), I'm running 2-3 miles an hour faster than they are, which would be about right considering cage gauges are about that much off on the low side.

I think they must be pretty close....
 
Old Sep 7, 2006 | 06:40 PM
  #8  
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Default RE: HD speedometer accuracy

Just rode past a portable radar display and my speedo read 37 and the police display read 36mph...........accurate enough for me
 
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Old Sep 7, 2006 | 07:24 PM
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Default RE: HD speedometer accuracy

My GPS is set on MPH. My Road King Classic is spot on at all speeds. My Sportster Roadster indicates 5 mph too much from about 35 mph on up. I just allow for it, although when the Sportster goes in for the 10k mile service, I will mention it to the Service Writer. .... BC
 
Old Sep 7, 2006 | 07:35 PM
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Default RE: HD speedometer accuracy


ORIGINAL: Hogmonger

I've done a lot of rides w/ my GPS and it is always right on (or at least +/- 1 mph, hard to tell with an analog speedo). Even at higher speeds it is VERY close.
Same here, cross-checking with GPS (in statute miles...).
 



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