Speedometer and odometer not matching up

[Camstyn]

So my speedometer reads 10% fast, which sounds like it’s normal.. But it’s interesting that the odometer is very close to accurate, when comparing to my GPS it is only slightly over 1% off.

 

Who cares, you ask? Well, I bought a set of ABS rings to correct the speedometer, but if I install them then my odometer will be almost 10% off. Strange.

[WRXer]

quite typical for most bikes

Edited September 19, 2021 by WRXer
edit

[Hibobb]

59 minutes ago, Camstyn said:

Who cares, you ask?

Now check your MPG on your screen vs real life miles driven/gallons used. Nothing on this computerized instrument panel seems to match up. Heck, even the ambient air temperature seems questionable. I miss the old days... when ignorance was bliss.

[Camstyn]

1 hour ago, WRXer said:

quite typical for most bikes

I always assumed that if the speedometer was off by 10%, the odometer would be too. Seems weird that they do not correlate. I guess I’ll keep the stock ABs rings on, I’d rather my speedometer be out than my odometer for trip planning, etc.

[Camstyn]

39 minutes ago, Hibobb said:

Now check your MPG on your screen vs real life miles driven/gallons used. Nothing on this computerized instrument panel seems to match up. Heck, even the ambient air temperature seems questionable. I miss the old days... when ignorance was bliss.

MPG calibration is always iffy with any vehicle. Sometimes they nail it, sometimes they’re out to lunch. Mine actually seems pretty accurate. I only trust my ambient air temp sensor when I’m moving, not when stopped.

Edited September 19, 2021 by Camstyn

[WalterT]

This has to do with regulations. The speedometer must show a speed with is (from memory) at least 5% more than the true speed. The odometer however must be within a few percent (allowing for tire wear etc). Partly to do with the manufacturers not getting blamed for a speeding ticket because the speedo is off.

The values shown in the displayed are therefore not the measured values, but calculated, and do not match up. 

[Toei]

ECE-R39 in Europe requires speedometers to not read below actual speed at all, and at most 10% over actual speed.  So the margin for error is all on the side of faster indicated speed.  To hit in the middle of the margin for error would end up around 5% over as you mention.

 

So the speedometers are calibrated to run high to avoid running afoul of European law, but it's done in the speedometer not at the input end.  It doesn't apply to odometers at all, so those should be accurate from the factory. 

[Landshark]

All we want is accuracy.  If you trust me riding the bike, you should trust I'll use and read the speedometer and odometer correctly.  There's no excuse for data that's incorrect.  I have sent Yamaha Canada a note on this but sadly, no response.

[Wintersdark]

14 hours ago, Landshark said:

All we want is accuracy.  If you trust me riding the bike, you should trust I'll use and read the speedometer and odometer correctly.  There's no excuse for data that's incorrect.  I have sent Yamaha Canada a note on this but sadly, no response.

For sure, but to be honest *every* vehicle - cars, trucks, bikes - I've every owned or measured has had this issue.  

 

@Toei is correct in that they're deliberately calibrated to read high so there's never a situation(running OEM or recommended equipment) where it'll read low, as aside from European laws, that would open them to a world of liability in the case of traffic violations, or worse, accidents.   If you could demonstrate the speedometer read low, you could use that as an excuse/cause.

 

I totally agree though that I'd far rather my speedometer just be accurate.