Speedometer error on speed?

[SilverBullet]

With my Gen 1, I just figure my spedo is showing roughly 4-5 mph faster then the actual speed, makes it easy. I have a GPS, but a lot of the time, it is easier to look at the spedo.

+1
And if you get a Speedohealer to correct your speedometer then it throws off your odometer. I'd rather have a accurate odometer tham speedometer because I speed all the time anyway so it doesn't matter. LOL

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[WJBertrand]

+1
And if you get a Speedohealer to correct your speedometer then it throws off your odometer. I'd rather have a accurate odometer tham speedometer because I speed all the time anyway so it doesn't matter. LOL

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True, but there are tighter laws regarding odometer accuracy (as you might imagine) compared to speedometer accuracy and you can't assume the same error percentage for both. My 2005 ST1300 had a 7% speedometer error but only a 2% odometer error doing extensive analysis vs. GPS speed and mileage.

 

[HeliMark]

True, but there are tighter laws regarding odometer accuracy (as you might imagine) compared to speedometer accuracy and you can't assume the same error percentage for both. My 2005 ST1300 had a 7% speedometer error but only a 2% odometer error doing extensive analysis vs. GPS speed and mileage.

I know to some people, a 3-7% odometer/speedometer error is a lot, but say 7K over 100k miles to me is insignificant, especially with this engine. Reality is at 100K, you would really be at 93K. Doing regular maintenance over those miles to me makes it all a non-event.

Now if we were talking about an aircraft engine, it would be a different story.

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[SilverBullet]

I know to some people, a 3-7% odometer/speedometer error is a lot, but say 7K over 100k miles to me is insignificant, especially with this engine. Reality is at 100K, you would really be at 93K. Doing regular maintenance over those miles to me makes it all a non-event.

Now if we were talking about an aircraft engine, it would be a different story.

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For me it's more about matching miles to road signs and accurately calculated mpg.

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[fredz43]

I should have clarified that the Gen 2 models sent to the US have improved accuracy. The post from the gentleman from Nova Scotia is another example of what we have seen in that Gen 2's shipped to other locations did not benefit from that update. Don't know why Yamaha did that, but they did.

 

[Byron]

Sounds like Canada=anal on speeding

LOL, in the southeastern states the law will allow 9 mph over the speed limit. So, yeah, very anal on speed. I'm always on cruise control and always around 8-9 mph over limit on the highway.

 

[HeliMark]

LOL, in the southeastern states the law will allow 9 mph over the speed limit. So, yeah, very anal on speed. I'm always on cruise control and always around 8-9 mph over limit on the highway.

I think you mean "law" as being the officers, as the actual "law" technically does not allow it. As a general rule of thumb, most LEO's in every state use the 10 over to not only give a little leeway, some speedo errors, and most important, less fight in court. Just don't depend on this in a small town needing revenue.

 

[Byron]

I think you mean "law" as being the officers, as the actual "law" technically does not allow it. As a general rule of thumb, most LEO's in every state use the 10 over to not only give a little leeway, some speedo errors, and most important, less fight in court. Just don't depend on this in a small town needing revenue.

Oh, I fully understand the revenue! I live on cruise control to keep myself out of trouble, unless I'm in Tennessee running the Dragon!

 

[Jlq1969]

All car manufacturers have an induced error, firstly, to comply with existing legal regulations (SAE J1226) and (ECE324) and secondly, to avoid a claim in case of an accident,

 

[Longdog Cymru]

Jlq1969 is right on the money. Here in U.K. various Police forces have tolerances for speed cameras,

https://www.autoexpress.co.uk/car-news/106674/uk-speed-camera-tolerances-revealed-is-your-cars-speedo-accurate

While the legal requirements are as follows;


The law for car speedometers in the UK
The UK law is based on the EU standard, with some minor changes. A speedo must never show less than the actual speed, and must never show more than 110% of actual speed + 6.25mph.
So if your true speed is 40mph, your speedo could legally be reading up to 50.25mph but never less than 40mph. Or to put it another way, if your speedo is reading 50mph, you won’t be doing more than 50mph but it’s possible you might actually only be travelling at 40mph.
To ensure that they comply with the law and make sure that their speedometers are never showing less than true speed under any foreseeable circumstances, car manufacturers will normally deliberately calibrate their speedos to read ‘high’ by a certain amount. As your satnav is not the designated device by which a car’s speed is measured, it does not need to incorporate any fudge factoring.

 

[fredz43]

I guess GM was unaware that they should have induced error, as my Cadillac CTS is right on the money and my Chevy HHR reads 1 mph slower than actual at 70 mph.

 

[Cycledude]

I have never actually checked the accuracy of the odometer but I do believe the miles add up quite a bit faster than reality, one of my friends rides a BMW and at the end of a day his always seems to show considerable less miles than the Tenere’s in our group.

 

[Checkswrecks]

I guess GM was unaware that they should have induced error, as my Cadillac CTS is right on the money and my Chevy HHR reads 1 mph slower than actual at 70 mph.

GM is fully aware and jiq1969 pulled the correct citation for what is going on.

The vehicle can be spot-on like your Caddy but if in testing it is found to indicate slower than reality, U.S. NHTSA can pull the authority to sell ANY of the model till the mfg fixes the problem, PLUS issue a mandatory recall. The reason I've heard from a NHTSA guy for this is that the crashworthiness safety standards are related to specific test speeds. If the car indicates 35 when actually going faster, it could easily not protect the occupants the way it is designed and tested to do. (imho - That 35 mph standard is DECADES obsolete and should be replaced with something progressively tighter, similar to mpg standards.)

As for your HHR, my guess is that the 1 mph is tire-related.

 

[Sierra1]

I think you mean "law" as being the officers, as the actual "law" technically does not allow it. As a general rule of thumb, most LEO's in every state use the 10 over....

AT LAST!!!!….somebody that gets it. I have heard "they have to give you 10mph...." for SO long. If the law allowed the extra 10mph....the signage would reflect it. Speed Limit....75mph + 10mph. And, as a "btw", I've used those roadside "this is your speed" radars numerous times to verify my speedo. My '17 has never shown more than 2mph below the speedo; likely the angle of the radar to the road. Most of the time the radar is only showing 1mph slower. Close enough for me. Because, like SilverBullet, I too am usually over the posted.

 

[VRODE]

My Gen2 '16 runs about 2-3 mph faster than my GPS at 65-75 mph. At lower speeds it's usually within 1 mph.

 

[fredz43]

GM is fully aware and jiq1969 pulled the correct citation for what is going on.

The vehicle can be spot-on like your Caddy but if in testing it is found to indicate slower than reality, U.S. NHTSA can pull the authority to sell ANY of the model till the mfg fixes the problem, PLUS issue a mandatory recall. The reason I've heard from a NHTSA guy for this is that the crashworthiness safety standards are related to specific test speeds. If the car indicates 35 when actually going faster, it could easily not protect the occupants the way it is designed and tested to do. (imho - That 35 mph standard is DECADES obsolete and should be replaced with something progressively tighter, similar to mpg standards.)

As for your HHR, my guess is that the 1 mph is tire-related.

Thanks for that, Bob.

So, it is known that some cars and motorcycles show speed that is considerably in excess of actual speed. It is also known that there is a citation that addresses this. In theory, then, all cars and motorcycles register speed that is in excess of actual speed because of that citation.

But..........in the words of an old wise man "In theory there is no difference between theory and practice. In practice, there is."

 

[Clawdog60]

Oh, I fully understand the revenue! I live on cruise control to keep myself out of trouble, unless I'm in Tennessee running the Dragon!

That didn’t work so well for me on the interstate in Texas this spring all though I was released with a warning. He tried to collect me with a car overtaking me doing 90 in an 80. Biker harassment!

 

[WJBertrand]

The old police saying; "9 you're fine, 10 you're mine" comes to mind....