fasteddy
Member
Since the speedometer reads 8% high, does it follow that the odometer also reads 8% high? Has anyone checked it out?
Odometer Error
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RossKean
Well-known member
I have found it to be slightly high (on my Canadian Gen II) compared to GPS, but only a percent or so - less than the speedo.
Not necessarily on multiple levels.
8% off of what exactly? Did you use a section of calibrated section of highway with mile-post markers, general MP markers, or maybe aerial marks used by aerial surveillance? What degree of accuracy is the 8%? +/- 2%? +/-0.5%?
And while the odometer is likely off consistently, the speedometer (depending on Gen) can be off different percentages at different indicated speeds. It maybe be off 7% at 20 mph, 8% at 70 mph, and 4% off at 100 mph. Calibrating it tends to be more difficult.
Also, which FJR? Different years and models may be off differently? Gen 1 & 2 are analog (and may be different between each other) than Gen 3 & 4. And tires can vary in diameter even within the same sizes including brand, make, and wear. And individual FJRs can vary as well.
The only way I could tell when I used to worry about it was to install and calibrate a Sigma bicycle odometer/speedometer and test compared to a calibrated road. Competitive rallies they'd have us run a calibrated course.
These days I know my speedo and odo are slightly optimistic and use my GPS receiver as a better indicator.
8% off of what exactly? Did you use a section of calibrated section of highway with mile-post markers, general MP markers, or maybe aerial marks used by aerial surveillance? What degree of accuracy is the 8%? +/- 2%? +/-0.5%?
And while the odometer is likely off consistently, the speedometer (depending on Gen) can be off different percentages at different indicated speeds. It maybe be off 7% at 20 mph, 8% at 70 mph, and 4% off at 100 mph. Calibrating it tends to be more difficult.
Also, which FJR? Different years and models may be off differently? Gen 1 & 2 are analog (and may be different between each other) than Gen 3 & 4. And tires can vary in diameter even within the same sizes including brand, make, and wear. And individual FJRs can vary as well.
The only way I could tell when I used to worry about it was to install and calibrate a Sigma bicycle odometer/speedometer and test compared to a calibrated road. Competitive rallies they'd have us run a calibrated course.
These days I know my speedo and odo are slightly optimistic and use my GPS receiver as a better indicator.
corrinarusso
New member
Oh wow, so the speedometer being wrong is a thing?? I had no idea. I have an 08, and it very consistently shows me driving at 4kms faster than those flashing speed signs. So in the 40km to 60km per hour range. Interesting. Should I "care" about it being wrong?
Should I be doing anything about it?
Corrie
Should I be doing anything about it?
Corrie
RossKean
Well-known member
Nothing "wrong" with it. Speedometers almost always indicate a higher speed than actual. (Not just FJRs)
Using a larger rear tire (190/55-17) will correct some of it (just a
Absolute error is pretty much proportional to speed and generally in the 5-10% range - harder to tell precisely with the analog speedometer on a Gen I or Gen II compared to the digital readout on later models. From what I have read, the speedo error seems to be higher on Canadian bikes than US bikes. I don't worry about it. If I want to know how fast I am going, I can make a mental correction or just glance at my GPS.
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corrinarusso
New member
Hi Ross,
Thanks for the detailed information.
This is the first I've heard of this.
And, good to know no action is required on my part! Lol
Trailrider57
Well-known member
When I had my 2012 if the GPS app on my phone said I was doing 70 my speedo would say I was doing 73. My buddies 2010 Gold Wing would be almost dead on with GPS. We then decided to compare the odometers. At 100 miles shown on the FJR he had only traveled 96. While none of this is proof it is an indicator that because the FJR speedo registers high it is also racking up miles faster than actual. As for my 2014, it shows about 72 mph when the GPS app is showing 70. I guess the plus side is if you set the cruise a few mph over the speed limit, and I do, you should still be close enough to avoid a ticket.
fasteddy
Member
My 2023 reads 8% high when compared to GPS and radar at various speeds. I have not checked the odometer. I believe that the speed sensor on the front wheel so changing rear tire size would not affect the speed reading. Simple question - has anyone checked the accuracy of the odometer?
RossKean
Well-known member
I thought it got vehicle speed from the rear wheel...
SkooterG
Purveyor of Crooked Facts
VSS (Vehicle Speed Sensor) changed locations slightly over the Gens but all measured in the transmission, so yes, the rear wheel.
Gen I FJRs speedo was off a couple mph. Odometer was off 2-3% optimistic.
Gen II FJRs speedo was off the most - around 5mph at 80mph or so. Don't know the odometer but I assume 2-3% optimistic.
Gen III FJRs speedo was most accurate. 82mph indicated = 80mph actual. Odometer probably off 2-3% optimistic.
Running a car tire makes the speedo more accurate. On a Gen III a car tire makes the speedo exact with no error. And the odometer error negligible - .1% optimistic.
From my 2013 with a car tire on an extended trip this past May:
RossKean
Well-known member
Your Gen II numbers are pretty close to what I see. Exact numbers are difficult with the Analog meter. The accuracy of the speedo with the CT (compared to GPS) is remarkable.
For prediction of the amount of correction you might expect with a tire change, the calculator linked (below) is great for computing differences between tires in terms of circumference and "error" at various speeds.
https://tiresize.com/comparison/
This cannot compensate for the "pinch" effect when you put a tire on a rim that is technically too narrow for it - results in larger diameter at the center of the tread and larger circumference...
torch
Well-known member
Compared to my GPS, my Canadian 06 is pretty close on the odometer (depending on tire wear) but definitely reads high on the speedometer by 4-5 kph @ highway speeds. I was told this is an artifact of European regulations since the Canadian speedo is also in kph and uses the same algorithm. The US ones in MPH are reputed to be more accurate.
My 03 was pretty close across the board.
My 03 was pretty close across the board.
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My odometer is perfectly accurate with its two readings:
(!.) You're not there yet,
(2.) You're there.
My speedometer exhibits similar accuracy with:
(1.) You're not moving
(2.) You're not moving fast enough
(!.) You're not there yet,
(2.) You're there.
My speedometer exhibits similar accuracy with:
(1.) You're not moving
(2.) You're not moving fast enough
This topic has been hashed over a number of times in the past 47 years. If you want to get your speedo in sync with your GPS all you need to do is change your rear tire to a 190-55. Not sure how that would work on a GenII but it worked on my 2014ES. It is dead on.
RossKean
Well-known member
A 190/55-17 has only about 1.6 % greater circumference compared to a 180/55-17. (About 1 mph difference at 60 mph.) As previously mentioned, Canadian FJRs seem to have a larger speedo error than US models - certainly more than the less-than 2% improvement for a 190 tire vs the 180. (As I mentioned before, the calculation doesn't account for a small increase in circumference due to pinching the tire on a narrower rim.)
Dang, no wonder I keep seeing those flashing lights in my mirrors....oh wait....% off in the other direction... 
I do not question your mathematical calculations but I can assure you I have checked my speedo against GPS and the occasional roadside speed indicators. In every case my speedo is exactly in sync with the other devices. I also think I get a bit more miles out of a 190. Oh, I forgot to mention it makes it a lot easier to get the bike up on the center stand. As a 82 year old 145 pound jackass that is a plus!!
RossKean
Well-known member
The math is right although doesn't account for the "pinch" effect or the fact that tire wear reduces the radius (and circumference) over time. I wouldn't expect these to be major factors, but haven't done the calculations.I do not question your mathematical calculations but I can assure you I have checked my speedo against GPS and the occasional roadside speed indicators. In every case my speedo is exactly in sync with the other devices. I also think I get a bit more miles out of a 190. Oh, I forgot to mention it makes it a lot easier to get the bike up on the center stand. As a 82 year old 145 pound jackass that is a plus!!
If I REALLY want to know how fast I am going, I look at my GPS, not my (analog) speedometer.
SkooterG
Purveyor of Crooked Facts
I do not question your mathematical calculations but I can assure you I have checked my speedo against GPS and the occasional roadside speed indicators. In every case my speedo is exactly in sync with the other devices. I also think I get a bit more miles out of a 190. Oh, I forgot to mention it makes it a lot easier to get the bike up on the center stand. As a 82 year old 145 pound jackass that is a plus!!
I've run two 190 rears and while the speedo and odometer were more accurate than the 180, and 'close' to being dead on, the 190 was not as accurate as the car tires I have run. That's my experience.
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