Odometer Inaccuracies

SPIKE ARRESTOR · 30th June 2011, 16:05

Yeah, sort of. The above point is also a reason for preference over positive error over negative error. We have to keep in mind that the instrument cluster / components provided by a supplier may be used in various platforms of a particular OEM.

Spike

rahul4640 · 30th June 2011, 20:34

I have the following free GPS based speedometer installed in my HTC mobile, a software downloaded from Android market.
http://market.android.com/details?id...=search_result
Several times I have seen that in my car the speedometer displays 110 KMPH when the GPS shows 100! And I have not upsized my tires.
Rahul Biswas
Calcutta

JustCause · 30th June 2011, 23:31

My car's speedometer is calibrated to be +10% of true value under most circumstances. Checked with Satnav system & GPS enabled phone. Tripmeter readings don't deviate more than the nearest hundred but, there is actually no way to verify the exact magnitude of deviation as there is only one digit after decimal.

Sheel · 1st July 2011, 00:26

When the Palio NV (the purple colored one) was launched, there were reports about Fiat calibrating the odo reading as it would show a bit more kilometers than it actually covered.

Reason? A slight bump while calculating FE figures so that owners would feel happy that their Palios are fuel efficient too.

lloydofcochin · 1st July 2011, 01:00

I have not noticed any Odometer error with my Palio SDX (Stock tires) but I have observed that post getting my Garmin unit the Top Speed that the Car touched was 140 kmph on the Speedo and on the GPS it showed the max speed of only 134 kmph which I guess is a minor error.

Mr.Boss · 1st July 2011, 03:55

Speedometers & Odometers are always manufactured with some tolerance (I'm not sure on the need though)

Even tyre wear affects speedo/odo readings. Approximately for every 1mm of tyre wear 0.5% error gets accumulated (recheck this values from the dynamic rolling radius of tyres)

BBR_SHR · 1st July 2011, 11:31

The instrument cluster has tolerances. Some leading auto magazines even publish the actual/measured values in their reviews. I would trust a GPS for distance/speed measurements over odo.

dhanushs · 1st July 2011, 14:42

Quote:

Originally Posted by BBR_SHR

I would trust a GPS for distance/speed measurements over odo.

AFAIK, GPS systems available commercially does not count the road gradient, and hence always will give slightly less than actual readings.

BBR_SHR · 1st July 2011, 17:19

Quote:

Originally Posted by dhanushs

AFAIK, GPS systems available commercially does not count the road gradient, and hence always will give slightly less than actual readings.

That is a very valid point to consider. Natural gradient + man made gradient et. al.

30th June 2011, 16:05	#16
SPIKE ARRESTOR Senior - BHPian Join Date: Nov 2009 Location: Germany Posts: 2,854 Thanked: 1,532 Times	Re: Odometer Inaccuracies Yeah, sort of. The above point is also a reason for preference over positive error over negative error. We have to keep in mind that the instrument cluster / components provided by a supplier may be used in various platforms of a particular OEM. Spike
	() Thanks

30th June 2011, 20:34	#17
rahul4640 BHPian Join Date: Feb 2011 Location: Calcutta Posts: 525 Thanked: 429 Times View My Garage	Re: Odometer Inaccuracies I have the following free GPS based speedometer installed in my HTC mobile, a software downloaded from Android market. http://market.android.com/details?id...=search_result Several times I have seen that in my car the speedometer displays 110 KMPH when the GPS shows 100! And I have not upsized my tires. Rahul Biswas Calcutta
	() Thanks

30th June 2011, 23:31	#18
JustCause BHPian Join Date: Apr 2010 Location: Currently, New Delhi Posts: 422 Thanked: 100 Times View My Garage	Re: Odometer Inaccuracies My car's speedometer is calibrated to be +10% of true value under most circumstances. Checked with Satnav system & GPS enabled phone. Tripmeter readings don't deviate more than the nearest hundred but, there is actually no way to verify the exact magnitude of deviation as there is only one digit after decimal.
	() Thanks

1st July 2011, 00:26	#19
Sheel Team-BHP Support Join Date: Jul 2006 Location: Purnea (Bihar) Posts: 9,588 Thanked: 14,404 Times View My Garage	Re: Odometer Inaccuracies When the Palio NV (the purple colored one) was launched, there were reports about Fiat calibrating the odo reading as it would show a bit more kilometers than it actually covered. Reason? A slight bump while calculating FE figures so that owners would feel happy that their Palios are fuel efficient too.
	() Thanks

1st July 2011, 01:00	#20
lloydofcochin BHPian Join Date: Apr 2009 Location: Bangalore Posts: 437 Thanked: 183 Times	Re: Odometer Inaccuracies I have not noticed any Odometer error with my Palio SDX (Stock tires) but I have observed that post getting my Garmin unit the Top Speed that the Car touched was 140 kmph on the Speedo and on the GPS it showed the max speed of only 134 kmph which I guess is a minor error.
	() Thanks

1st July 2011, 03:55	#21
Mr.Boss Distinguished - BHPian Join Date: Mar 2011 Location: GPS signal lost Posts: 2,811 Thanked: 7,464 Times View My Garage	Re: Odometer Inaccuracies Speedometers & Odometers are always manufactured with some tolerance (I'm not sure on the need though) Even tyre wear affects speedo/odo readings. Approximately for every 1mm of tyre wear 0.5% error gets accumulated (recheck this values from the dynamic rolling radius of tyres)
	() Thanks

1st July 2011, 11:31	#22
BBR_SHR BHPian Join Date: Jun 2011 Location: Bangalore Posts: 61 Thanked: 77 Times	Re: Odometer Inaccuracies The instrument cluster has tolerances. Some leading auto magazines even publish the actual/measured values in their reviews. I would trust a GPS for distance/speed measurements over odo.
	() Thanks