Mileage difference between ECU/Nav 5 and odometer

[RedRick Esq.]

My odometer is reading 4989 miles whereas the data bit on the Nav 5 is showing over 5000

So
Which one is correct and why is this the case ?

Anyone got any ideas or theories or better still facts

 

[Deleted account 190920001]

The bike is correct for the bike. Maybe the nav 5 is achieved via gps which can get screwed up depending on the area your in.

 

[Engineer]

Doesn't the Nav 5 read the data from the bike?

 

[Deleted account 190920001]

If it does it isn't doing it properly. Easy enough to prove, switch it off and leave it at home for a few trips.
I was thinking its the mileage the nav has traveled since you can get a car kit for it and all that.

 

[RedRick Esq.]

I thought the nav linked into the ECU which in its own case reads or feeds the odometer and the 2 should marry up so to speak

 

[Oilcracker]

GPS will be the truer reading. Provided it has been with the bike for all the 4989 miles your odometer is reading. My work van is tracked via GPS and that and the odometer readings differ quite a lot. The people from Navman who make the tracker have said that the vehicle odometer can be affected by things like vehicle weight and tyre pressures well that's what they have told us anyway. Comparing the Navman weekly data report with my garmin Nuvi I have run in the van the mileages are near as damn it the same.

 

[Deleted account 190920001]

GPS will be the truer reading. Provided it has been with the bike for all the 4989 miles your odometer is reading. My work van is tracked via GPS and that and the odometer readings differ quite a lot. The people from Navman who make the tracker have said that the vehicle odometer can be affected by things like vehicle weight and tyre pressures well that's what they have told us anyway. Comparing the Navman weekly data report with my garmin Nuvi I have run in the van the mileages are near as damn it the same.

I wouldn't agree with gps being truer. Drive through a built up city or through a tunnel, even a heavily forested area and gps doesn't work well.
I track cycle rides all the time with gps and even on the exact same route the distance can vary by a fair bit. The speed/wheel sensor is always the same though.

 

[Engineer]

I thought the nav linked into the ECU which in its own case reads or feeds the odometer and the 2 should marry up so to speak

that's what I thought because my odometer and the sat nav data are identical - I assume that you are referring to the Status data in the My Motorcycle app?

 

[RedRick Esq.]

that's what I thought because my odometer and the sat nav data are identical - I assume that you are referring to the Status data in the My Motorcycle app?

Yes thats the one
There seems to be about 240 miles variance between the two or there was when i looked this morning it may have sorted itself out i haven't checked since i got back from our ride but if this is the case that the 2 can vary it could be that when you buy one of these used the odo may not be telling the whole truth.

I shall make enquiries when it has its service on friday

 

[Engineer]

Yes thats the one
There seems to be about 240 miles variance between the two or there was when i looked this morning it may have sorted itself out i haven't checked since i got back from our ride but if this is the case that the 2 can vary it could be that when you buy one of these used the odo may not be telling the whole truth.

I shall make enquiries when it has its service on friday

hmmmmmm interesting, the used one will contain that bike's last data and I can't see a way of resetting it - maybe it will eventually get back in sync, it ought to.

perhaps I misunderstood your post? the odo on the bike should always be correct.

 

[Titto]

Yes thats the one
There seems to be about 240 miles variance between the two or there was when i looked this morning it may have sorted itself out i haven't checked since i got back from our ride but if this is the case that the 2 can vary it could be that when you buy one of these used the odo may not be telling the whole truth.

I shall make enquiries when it has its service on friday

Nice find! I would say it's likely a bug with the Garmin unit. Send a bug report to Garmin re the nav v, and hope they address it in future firmware updates. I'll do the same later, I have had good past experience with the zumo 550 and Garmin bug fixes.

 

[Nutty]

Now this is interesting. As most speedos are around 5-10% out, how many miles have our bikes REALLY done?

 

[RedRick Esq.]

To satisfy myself i have just checked the 2 readings again and they now say the same thing so it must have re synced or whatever which is a relief but odd that it was so different this morning pre ride

 

[Schtum]

To satisfy myself i have just checked the 2 readings again and they now say the same thing so it must have re synced or whatever which is a relief but odd that it was so different this morning pre ride

Apart from satisfying any potential OCD traits you might have, is this necessarily a good thing. I suspect that since the speedometer over-reads, the odometer does as well by about 5%. The GPS, on the other hand, should give you a more accurate speed reading and hence the displayed mileage has the potential to be more accurate.

 

[Engineer]

To satisfy myself i have just checked the 2 readings again and they now say the same thing so it must have re synced or whatever which is a relief but odd that it was so different this morning pre ride

I have assumed that the Nav V simply takes its data from the bike odometer and then displays it with the My Bike App - I guess it might also measure the distance travelled using GPS but what it does with that data and if it is displayed somewhere I haven't a clue.

 

[RedRick Esq.]

Apart from satisfying any potential OCD traits you might have, is this necessarily a good thing. I suspect that since the speedometer over-reads, the odometer does as well by about 5%. The GPS, on the other hand, should give you a more accurate speed reading and hence the displayed mileage has the potential to be more accurate.

Now that they both read the same I can only conclude that the the Odometer supplies the ECU which in turn is synced with the Nav !
Yes the Nav gives a more accurate speed reading which is as you suggest lower than the Speedo.
Next time i do a decent long run i will compare the miles clocked on the odometer against the miles the Nav says i have done ( the nav mileage on trips is based on GPS rather than odo )

Which may or may not give a percentage difference which can be pro rata upscaled to see how many miles the bike has actually done versus the odo reading

Does that make sense ??

 

[Schtum]

Now that they both read the same I can only conclude that the the Odometer supplies the ECU which in turn is synced with the Nav !
Yes the Nav gives a more accurate speed reading which is as you suggest lower than the Speedo.
Next time i do a decent long run i will compare the miles clocked on the odometer against the miles the Nav says i have done ( the nav mileage on trips is based on GPS rather than odo )

Which may or may not give a percentage difference which can be pro rata upscaled to see how many miles the bike has actually done versus the odo reading

Does that make sense ??

So I was correct about the OCD then.....

 

[Engineer]

Now that they both read the same I can only conclude that the the Odometer supplies the ECU which in turn is synced with the Nav !
Yes the Nav gives a more accurate speed reading which is as you suggest lower than the Speedo.
Next time i do a decent long run i will compare the miles clocked on the odometer against the miles the Nav says i have done ( the nav mileage on trips is based on GPS rather than odo )

Which may or may not give a percentage difference which can be pro rata upscaled to see how many miles the bike has actually done versus the odo reading

Does that make sense ??

The confusing thing to me is that my Nav 5 and Mike bike odometer have never read differently as far as I remember - I will keep an eye on it. I assumed, maybe incorrectly, that the My Bike App simply reported the bike odometer??????.

 

[RedRick Esq.]

So I was correct about the OCD then.....

No !
I was pandering to yours !

Although i do like cleaning shoes

 

[Deleted account 190920001]

That's confirms what gives what reading then.
I have checked the odometer accuracy before and found on computer ran things it is correct or as correct as it can be given tyre ware and or tyre pressures. It is only the speed that is deliberately offset. Manufactures don't want a pile of complaints from people who got a ticket.