Speedometer accuracy

[Claude]

2017 100% stock FZ07

I'm used to speedo being off (optimistic) by 2% to 5% but on my FZ, it is off by 7% (107 kph indicated vs 100 kph GPS) which is non negligible. Is my speedo "normal" compared to yours?

Thanks!

[mjh937]

I have not done any high speed checks but every time I have driven by one of those devices by the road that shows what your speed is relative to the speed limit is it has been right on.  I think the fastest has been 35 mph though, so maybe is off when I get faster. 

[Claude]

8 hours ago, mjh937 said:

I have not done any high speed checks but every time I have driven by one of those devices by the road that shows what your speed is relative to the speed limit is it has been right on.  I think the fastest has been 35 mph though, so maybe is off when I get faster. 

When I drive by those, they show the same speed than my GPS. So, it confirms my speedo to be off by 7%.

Edited May 11, 2023 by Claude
typo

[Triple Jim]

That seems excessive.  My 2020 is about 1.5 MPH high at 60.

[Max of Millbrook]

My speedo is off by 5 kph every radar I go through. I recently used a reliable km posting and found my odometer to be indicating 52 kms in real 50 km post. That means this bike is putting on 4 kms every 100 kms. In the old days the front wheel had a cable drive. This bike must have a digital axle ratio in the ECU. When I have the bike on the rear lift the odometer/speedo sctually runs.

Anyway to correct this?

 

[mjh937]

I know the non-ABS bikes are computing the speed off the transmission somehow (there is a cable that goes in to the engine housing).  The ABS bikes use the speed sensor ring on the wheel.  I am not sure if it the front or back wheel (my bike does not have ABS). 

[Grip it & Rip it]

15 hours ago, mjh937 said:

I know the non-ABS bikes are computing the speed off the transmission somehow (there is a cable that goes in to the engine housing).  The ABS bikes use the speed sensor ring on the wheel.  I am not sure if it the front or back wheel (my bike does not have ABS). 

speed sensor ring is on the front wheel

[ElGonzales]

12 hours ago, Grip it & Rip it said:

speed sensor ring is on the front wheel

Perhaps, but every manual says it's the sensor ring of the rear wheel.

And I know you guys don't believe anything internet stranger or service manuals say (what's cool), so I just did a scientific experiment with my ABS bike:
 

And the speedo can't be absolutely accurate. In many countries it's not allowed by law that the speedometer shows less speed than you're actually riding. Not a single digit. We have differences in the outer diameters of the tire types and it decreases with the loss of profile. Different air pressures...  But the speed calculation is done by the number of wheel revolutions (the assumed travelling distance) per time which can never be exactly the same for a certain speed. So the makers have so plan a security margin to stay street legal with their vehicles.

Edited August 11, 2023 by ElGonzales

[Claude]

If the speedometer is wheel’s rotation monitored, then I assume an optimistic reading could be lowered by a slightly taller tire (which would result in a wheel turning slightly slower). I’ll look at this option when tire will be due.

Edited August 11, 2023 by Claude
Typo

[ElGonzales]

2 hours ago, Claude said:

If the speedometer is wheel’s rotation monitored, then I assume an optimistic reading could be lowered by a slightly taller tire (which would result in a wheel turning slightly slower). I’ll look at this option when tire will be due.

Yes, but there is also another solution.
A company called Healtech that offers a device called "Speedohealer"
Their website is:
https://www.healtech-electronics.com/products/sh/

The installation manual is in english: https://www.healtech.at/images/Anleitungen SH V4/SH-U01__Yamaha_MT-07_(ABS)__2014-.pdf

As you can see, the device is connected to the wire which transports the speed signal between ABS control unit and the ECU.
Then you can manipulate your displayed speed like you want to. But I have no personal experience with that device, I don't need it.

I think some people here also use it, at least I read about it in the online communities. 


 

[Advmgn]

The Speedo on my 2015 is dead on at 65 mph.

I use the SpeedoDRD by 12 o'clock labs on two of my other bikes and it works well.

It costs less than a Speedo Healer. 

[Claude]

13 hours ago, Advmgn said:

The Speedo on my 2015 is dead on at 65 mph.

I use the SpeedoDRD by 12 o'clock labs on two of my other bikes and it works well.

It costs less than a Speedo Healer. 

I just looked on their website and they only lists the non ABS FZ07 (mine have ABS). I emailed them so we’ll see.

[Max of Millbrook]

On 8/10/2023 at 4:38 PM, Grip it & Rip it said:

speed sensor ring is on the front wheel

Well that's funny because when I have the bike up on the rear stand, lube the chain and run it in 1st the speedo indicates the speed. I believe the speedo drive is on the output shaft. I should have disconnected the rear abs sensor and tried it. Another time.

[Max of Millbrook]

On 5/13/2023 at 5:59 PM, Triple Jim said:

That seems excessive.  My 2020 is about 1.5 MPH high at 60.

I bought a 2019 in 2021 NOS. It is consistly 5 km fast at all radar posts! I just did a run of 50 kms and according to the posts the mileage was at 3.5 kms over actual! So at 50,000 kms. It is logging excessive mileage.

[tomlichu]

6 hours ago, Max of Millbrook said:

I believe the speedo drive is on the output shaft.

It should be the rear wheel sensor

[Max of Millbrook]

Thanks. Great information.

5 hours ago, tomlichu said:

It should be the rear wheel sensor

Thanks. Great information.

But there is no way to fix this?

The speedo has been out since new.  Could the sensor be counting wrong?

[Claude]

17 hours ago, Max of Millbrook said:

Well that's funny because when I have the bike up on the rear stand, lube the chain and run it in 1st the speedo indicates the speed. I believe the speedo drive is on the output shaft. I should have disconnected the rear abs sensor and tried it. Another time.

Same here. Lubing chain on rear stand and engine running in 1st gear shows the speed on speedo. Same thing when turning the wheel by hand in neutral, engine not running and ignition to "on". FWIW, speed is shown even with the wheel turning backward. I understand why; just passing the info.

[tomlichu]

7 hours ago, Max of Millbrook said:

Could the sensor be counting wrong?

Hard to say. When I drive my car, 80 mph is actually 76 mph. A road trip I took was 830 miles via Googlemaps, but I measured like 880 miles on my ODO. However, my tire is worn, so every wheel rotation is less distance traveled, which is likely causing this discrepancy. If the sensor rotor appears bent, I would replace it. Your speedometer will not be 100% accurate.

I am guessing the speed sensor is a hall effect sensor. If that is the case, the sensor needs to be as close to the ring as possible. Hall effect sensors measure the magnitude of a magnetic field. The sensor is measuring the wheel rpm by using the slotted portion of the sensor ring and measuring the time it takes for the wheel to travel the width of one slot. If your sensor is broken, it might be an issue with wiring more than the sensor itself. Unplug the sensor and check for rust in the connections.

[Triple Jim]

The speed sensor either senses metal or the lack of metal (hole) in the disk.  It's not going to be off by some steady fixed percent.  If something is marginal and the sensor occasionally misses seeing a hole, it's not going to give a steady reading that's x% off.  My guess is that something between the speed sensor and the display is miscalibrated.

[tomlichu]

55 minutes ago, Triple Jim said:

The speed sensor either senses metal or the lack of metal (hole) in the disk.  It's not going to be off by some steady fixed percent.  If something is marginal and the sensor occasionally misses seeing a hole, it's not going to give a steady reading that's x% off.  My guess is that something between the speed sensor and the display is miscalibrated.

Yeah, that would make sense. My car is off linearly to speed, the faster I drive my car, the bigger the difference is between my speedo and GPS speed.

Is your speed difference the same at 50 kph vs 100 kph?

[Triple Jim]

5 minutes ago, tomlichu said:

Is your speed difference the same at 50 kph vs 100 kph?

No, the error is proportional to speed.  Since it's 1.5 mph high at 60, that means it reads about 2.5% high.

There is another error that comes in when the driving force to the rear wheel is high, like when you're going very fast, and that's tire creep.  Even when you're not spinning the rear wheel, it rotates just a little faster when it's being driven than when you're coasting.  I don't know how big this error is, but on a different motorcycle I've measured speedometer error getting worse as I speed up,  as a percentage of speed.  I noticed this on my Moto Guzzi that also measured speed from the rear wheel, and it seemed to add a couple more percent to the error as I got up over 80 mph.  That's a reason to measure speed from a non-driven wheel if you want top accuracy.

I have not checked the accuracy of my MT-07 speedometer at high speeds, like 80 mph or higher.  For practical purposes, a speedometer being within a couple percent of perfect is more than plenty accurate.

[flLen Soull]

@Claude - My comment most likely does not help. But i have noticed the same on my 2021 MT07.

I have not done any extensive checking ont his behaviour yet, but I did notice the other week when I did a trip, that my bike was showing 7km/h less than the GPS speed coming from my phone.

I had the same issue with my KLX250 which the speed scensor is on the front wheel.  So when i ride on the motorway, I will sit between 107 to 110km/h on the speedo and that will give me roughtly 100km/h.

I still need to confirm lower speed but if it's like my KLX then i am going to guess when I do 60km/h by the speedo I will in fact be doing 55km/h

Since both my bike behaved this way, I thought that is the nature of motorcyle speedos.

 

 

[Claude]

On 8/12/2023 at 8:45 PM, Advmgn said:

The Speedo on my 2015 is dead on at 65 mph.

I use the SpeedoDRD by 12 o'clock labs on two of my other bikes and it works well.

It costs less than a Speedo Healer. 

****** THREAD REVIVAL ******

FWIW, I ordered and installed (last week) a SpeedoDRD. FZ07 with ABS is not listed on their website simply because they only lists bikes which have a plug'n play installation. On my ABS'd bike, the installation involve some wiring at three wires of the ECU connector (nowhere else) and it is quite easy to do. I installed mine and programmed a -6.2% display.

 I took my first 2024 ride today and the speedo is now exactly where I believe it should be, at least between 90 and 120 kph. At those speeds, the speedo is showing between 0 and 1 kph more than my gps. However, between 50 and 80 kph, it is about 1~2 kph optimistic. I'll leaving it as is and it's perfectly acceptable for me.

Thanks to Advmgn for posting about SpeedoDRD !!! I saved many bucks over choosing a Speedo Healer.

Edited April 9 by Claude

[Claude]

21 hours ago, Claude said:

... At those speeds (between 90 and 120 kph), the speedo is showing between 0 and 1 kph more than my gps. However, between 50 and 80 kph, it is about 1~2 kph optimistic. I'll leaving it as is and it's perfectly acceptable for me...

Just to add about my words above. The SpeedoDRD device is made to change the speedo display at the programmed rate. In my case, I programmed -6.2%

So, if the display is 2 KPH optimistic between 50 and 80 kph, it's because of the programmation Yamaha dropped in the ECU. SpeedoDRD is still lowering the display by 6.2% but the numbers are a bit high to start with so it remains a bit high but only by 6.2% less. (Hope I'm clear enough [french speaking guy here trying to clearly explain something technical...]).

I wanted to clarify this only to be sure I was not blaming SpeedoDRD device of giving a too high display between 50 and 80 kph; it's Yamaha's fault (but a very minor one I must say).