Speedometer not accurate
12-19-2008, 02:29 PM
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Originally Posted by porsche911targa' post='749023' date='Dec 19 2008, 06:20 PM
My apologies for reviving such an old thread. OK, I have just verified with two different GPS devices that my speedometer also reads 3 MPH faster across all speeds. This may not seem like much, but for someone who drives back roads 99% of the time with average speed of 25.2MPH, I calculated that the odometer should be off significantly , since the average speed shown in the computer should really be 22.2MPH. So 22.2/25.2 gives a correction factor of .89. .89x38,000 (current odo reading) = 33,820
In effect my car's real mileage is 33,280 and not the 38,000 miles indicated by the odometer. At this rate by the time the odo reads 100,000 (when CPO and extended maintenance expires) the real mileage should be 89,000 miles.
This is shocking to say the least. I would like to research if there is some sort of class action suit going on or if it would be worth starting one. The implication for such gross mileage misrepresentation is huge. For one thing, your warranty period expires much sooner than it should and it also affects the resale value. Has anybody dealt with BMW with this specific issue? If I were to request my dealer to calibrate the speedometer to pretty much negligible speed difference, will they do it under warranty?
Just as a side note. We tried the GPS on a friend's Camry and the speed was a perfect match.
TIA
In effect my car's real mileage is 33,280 and not the 38,000 miles indicated by the odometer. At this rate by the time the odo reads 100,000 (when CPO and extended maintenance expires) the real mileage should be 89,000 miles.
This is shocking to say the least. I would like to research if there is some sort of class action suit going on or if it would be worth starting one. The implication for such gross mileage misrepresentation is huge. For one thing, your warranty period expires much sooner than it should and it also affects the resale value. Has anybody dealt with BMW with this specific issue? If I were to request my dealer to calibrate the speedometer to pretty much negligible speed difference, will they do it under warranty?
Just as a side note. We tried the GPS on a friend's Camry and the speed was a perfect match.
TIA
I dont think thats quite right. That assumes that the computer is using your speed and time to calculate the distance. I believe that the mileage is actually calculated without taking your average or instantaneous speed into account. The only effect of this is showing higher speeds to convince drivers that they are going faster than they really are so that they dont push the limit too far. Just my thought on the subect but I could be wrong.
12-19-2008, 04:10 PM
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+1
I think you're right, nikko64. What's more, this chronically high reading of BMW speedos is at least 25 years old, and I'm sure I've read some knowledgeable source that it is on purpose, something to do with the way BMW (and Audi, and...?) comply with a German law applying to motor vehicle manufacturers... can't remember the details, but it made sense wherever I stumbled across it.
It's just a little cushion that hopefully keeps you out of the big problems.... Have fun with your bimmer,
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I think you're right, nikko64. What's more, this chronically high reading of BMW speedos is at least 25 years old, and I'm sure I've read some knowledgeable source that it is on purpose, something to do with the way BMW (and Audi, and...?) comply with a German law applying to motor vehicle manufacturers... can't remember the details, but it made sense wherever I stumbled across it.
It's just a little cushion that hopefully keeps you out of the big problems.... Have fun with your bimmer,
Cal
12-19-2008, 06:18 PM
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Originally Posted by nikko64' post='749088' date='Dec 19 2008, 06:29 PM
I dont think thats quite right. That assumes that the computer is using your speed and time to calculate the distance. I believe that the mileage is actually calculated without taking your average or instantaneous speed into account. The only effect of this is showing higher speeds to convince drivers that they are going faster than they really are so that they dont push the limit too far. Just my thought on the subect but I could be wrong.
12-19-2008, 06:23 PM
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Originally Posted by luigi524td' post='749043' date='Dec 19 2008, 05:38 PM
I'm disappointed that many posters are reporting inaccurate speedometers.
I've confirmed my '07 e60 against two different Nav systems at a steady 40 mph and 60 mph and my speedometer is spot on. My car has original equipment Bridgestone tires and I estimate the tread depth is about 80% of new. Tire wear will have an (negligible) effect on speedometer ... and new vs totally worn out tires will result in speed variation.
I also think the speedometers on BMWs can be calibrated electronically ... if the speedo is off more than 2-3 mph it might be wise to have it validated / corrected.
I've confirmed my '07 e60 against two different Nav systems at a steady 40 mph and 60 mph and my speedometer is spot on. My car has original equipment Bridgestone tires and I estimate the tread depth is about 80% of new. Tire wear will have an (negligible) effect on speedometer ... and new vs totally worn out tires will result in speed variation.
I also think the speedometers on BMWs can be calibrated electronically ... if the speedo is off more than 2-3 mph it might be wise to have it validated / corrected.
I'm feeling speedo-dysfunctional - and have made an appointment with my BMW SA and will insist that my speedometer be uncorrected!
12-20-2008, 06:47 AM
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On Monday, I will measure the mileage on the odometer to work and compare it to the mileage shown on the GPS and I will report my findings.
12-20-2008, 07:00 AM
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Originally Posted by porsche911targa' post='749394' date='Dec 20 2008, 11:47 AM
On Monday, I will measure the mileage on the odometer to work and compare it to the mileage shown on the GPS and I will report my findings.
Please do. Im looking forward to this little experiment.
Realistically, though, Im sure bmw has a large number of engineers AND lawyers who have already verified this to avoid lawsuits. But what the hell, maybe we can all get the mods paid for if the odometers are inaccurate
12-20-2008, 09:06 AM
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Got to go against the consensus.
I have repeatedly checked my W60 speed with a hand held GPS receiver and found it to be accurate within one mph. Similarly, elapsed miles were within two miles in a 400+ mile trip.
But then, I don?t believe in manmade global warming. So what do I know?
I have repeatedly checked my W60 speed with a hand held GPS receiver and found it to be accurate within one mph. Similarly, elapsed miles were within two miles in a 400+ mile trip.
But then, I don?t believe in manmade global warming. So what do I know?
12-20-2008, 11:23 AM
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I think you're the only person I've ever read on these threads (there have been many over the years), that has reported accurate speedo results... try another GPS?? 
12-20-2008, 11:57 AM
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Originally Posted by calpalmer' post='749540' date='Dec 20 2008, 03:23 PM
I think you're the only person I've ever read on these threads (there have been many over the years), that has reported accurate speedo results... try another GPS??
OK, I will take up your suggestion, I do have a portable Magellan. Will check it out and advise.