Speedo Accuracy

[Craigmri]

This is the first bike I ever owned(and I've had many) that the speedo is dead nuts on par with my GPS. Sweet! BTW, this is my GPS setup. Still havent ran power up to it yet as the Honda relay kit is on backorder but tested the mount this morning and its fantastic!

 

[670cc]

Yes, US spec models have accurate speedos (with fresh OEM size rear tire). As the rear tire wears you'll start to see a little error. Outside the US (not sure about Canada), riders report a 5% to 8% optimistic speedometer error. The speed pickup sensor is at a transmission input shaft gear. If you change sprocket or rear tire sizes the speedo accuracy will change.

Old posts:

http://nc700-forum.com/forum/nc700-technical/474-speedo-off.html

http://nc700-forum.com/forum/nc700-general-discussion/329-honda-nc700x-xd-dct-top-speed-speedo-accuracy.html

 

[johnakay]

mine is accurate at 30mph not sure there after.

 

[Chestnut]

Mine is off 1mph at any reasonable speed and 2mph during especially long, straight, traffic-free stretches of desert.

 

[StratTuner]

at 60 and above, it's off by 1. My speedometer says 71 and the GPS says 70.

 

[Craigmri]

Thats pretty darn close for a motorcycle speedo. Most all of my bikes always read optimistic by 5% or more!

at 60 and above, it's off by 1. My speedometer says 71 and the GPS says 70.

 

[FrankQC]

You are lucky guys... My Canadian NCX is off a steady 8%, Whatever the speed. If my speedo says 120 Km/h, my actual real speed is 110. If it says 60, my real speed is 55... That is with the OEM Metzeler with the right pressure.

 

[happy]

 

[mfb]

mine is upto 8% off with 500km on the odometer. I think it will push 10% once the tires are worn.

 

[MZ5]

A purely innocent question:
What makes one think that one's gps-reported speed is more accurate than anything else?
(not that I haven't made this same comparison on any number of vehicles)

 

[dduelin]

Because GPS is proven to be accurate. Ships, planes, and nuclear missiles normally know their position within 1.5 meters. Modern units are astonishing accurate given the slow speeds bikes move at on normal roads. Older single channel multiplexing units in the days of signal dithering not so much. GPS calculates speed from distance divided by time and updates this up to several times a second. There are some errors from incorrect position but since they are so few and the unit updates so often the average speed error is in the neighborhood of .01%.

 

[Naked_Duc]

From my distance comparison, the NCX's odometer is accurate to maps. So therefore, I would say the speedo is accurate as well.

 

[mfb]

actually the bike knows the sort of real speed but shows an intentional high number in Europe to conform due to "the speedo may not show over the actual vehicle speed and shall not have more than 10% error on the display" rule (it is an EC regulation I read about a few years ago). In some analog bikes you should see an equivalent odometer error to the speedometer error. In most recent (not all) bikes, the odometer is mostly accurate (0-X% based on tire wear, laden weight, ambient temp, tire size difference from the factory original and inflation pressure) but the display shows a higher speed value on the speedometer. Apparently our NC is accurate on the odometer.

As per UN/ECE Regulation Nr 39 para. 5.3:
"The speed indicated shall not be less than the true speed of the vehicle. At the test speeds specified in paragraph 5.2.5 above, there shall be the following relationship between the speed displayed (V 1 ) and the true speed (V 2 ).
0 ≤ (V 1 – V 2 ) ≤ 0,1 V 2 + 4 km/h"

you may find the full text at:http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:120:0040:0048:ENDF

 

[FrankQC]

From my distance comparison, the NCX's odometer is accurate to maps. So therefore, I would say the speedo is accurate as well.

Exactly as mfb said. The odometer is accurate, but not the speedo. It looks like the speedo is off by purpose. I guess Honda doesn't want us to blame them saying "I got a 65 mph ticket but the speedo was showing 58...It's Honda fault". I had several bikes (many Honda and 3 Suzuki), they were all optimistic on the speedo speed, between 5-8 % over the real speed. My 2008 GL1800 was off 8% and so is this NC700.

 

[mfb]

Exactly as mfb said. The odometer is accurate, but not the speedo. It looks like the speedo is off by purpose. I guess Honda doesn't want us to blame them saying "I got a 65 mph ticket but the speedo was showing 58...It's Honda fault". I had several bikes (many Honda and 3 Suzuki), they were all optimistic on the speedo speed, between 5-8 % over the real speed. My 2008 GL1800 was off 8% and so is this NC700.

It is more likely a regulation issue than Honda's fault. Without passing all ECE regulation tests, one cannot register a vehicle in Europe any other UN/ECE norm country. The exceptions I am aware of are the SAE regulations in US and other Nafta countries and Japanese regulations.

So they are actually liable to supply you a vehicle that conforms to these standards (errors in this case) during the lifetime of the vehicle within the defined use limitations specified by the regulations. e.g. US and Nafta vehicles have to be certified as per SAE standards and not by UN/ECE standards.

 

[FrankQC]

It is more likely a regulation issue than Honda's fault. Without passing all ECE regulation tests, one cannot register a vehicle in Europe any other UN/ECE norm country. The exceptions I am aware of are the SAE regulations in US and other Nafta countries and Japanese regulations.

So they are actually liable to supply you a vehicle that conforms to these standards (errors in this case) during the lifetime of the vehicle within the defined use limitations specified by the regulations. e.g. US and Nafta vehicles have to be certified as per SAE standards and not by UN/ECE standards.

I didn't meant to say it was Honda's fault, i meant that was done on purpose to not blame them for a speeding ticket. Why would they make it off by purpose ? Like I said, I've have several vehicles 5-8 % optimistic, but I've also had several dead on the actual speed.

 

[Jay Fridays]

My speedo said 95mph... The cop radar said 95mph.... bad for me... good for the Honda engineers....

 

[RiderCoach]

Mine is also dead on with the GPS. This is the only bike I've ever had where the speedo matched the GPS.

 

[StratTuner]

Speedo is very accurate... that's why I never wear them! Ohhh! Speedometer! OK.... never mind....

 

[MZ5]

Because GPS is proven to be accurate. Ships, planes, and nuclear missiles normally know their position within 1.5 meters. Modern units are astonishing accurate given the slow speeds bikes move at on normal roads. Older single channel multiplexing units in the days of signal dithering not so much. GPS calculates speed from distance divided by time and updates this up to several times a second. There are some errors from incorrect position but since they are so few and the unit updates so often the average speed error is in the neighborhood of .01%.

And I used to know where I was in some fields to within less than half an inch. That wasn't with the handheld units we get at the sporting goods counters, though.

I understand your point, but you're talking about GPS units in general (and military and commercial navigation units at that), not a given handheld consumer unit in particular. Have you calibrated your personal (non-military, non-commercial) gps unit? What did you calibrate it against?

Again I understand the point, and if it wasn't for the fact that I've been able to demonstrate a number of handheld units to be incorrect with respect to speed and/or speed over a known distance, I'd probably be more persuaded by the abstract argument you're making.