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06-20-2008, 08:30 AM | #1 |
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Speedometer off.
Hello all, as some have mentioned and I have verified with a gps, the speedo is about 3mph fast at 60 and progressively more so as speed increases.
I have two questions regarding this. Will/ can the dealer recalibrate it for me for free? Does it make a difference in the mileage of the vehicle? After all, I would assume (I am not an engineer) that the speedo is connected to the odometer, I am not sure there would be another way to seperately measure mileage. If this is the case and I drove a half an hour a day (roughly 1000 miles a month if assuming 60mph) My car would have an extra 550 miles on it a year. Not a lot, but if you lease (I don't but I feel like making an argument) that would be $110 dollars/ year. Now that doesn't seem like much, but I bet most of us would haggle over $10/month payment being the lowly and poor one series owners we are. Discuss.
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06-20-2008, 08:34 AM | #2 |
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I think that someone mentioned in another thread that while the speedometer is optimistic, for lack of a better word, the odometer remains spot-on as verified by a bunch of people in tests.
Having it be off by 3-5% seems like a huge liability that there's no reason BMW would want to take on, while 3-5% optimism in the speedometer could be in our best interest. |
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06-20-2008, 01:27 PM | #4 |
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Like other Euro manufacturers, BMW builds a small safety measure of optimism into speedometers so as not to run afoul of regs prohibiting an error on the slow side. Generally, the OBC readings are accurate, and the odometers are also accurate.
I've heard of dealers physically bending the speedo needle as a fix, but only if the error is really large - 10% or so. Tom |
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06-20-2008, 01:43 PM | #7 |
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This has been discussed a lot already. Yes the speedo is off, but it is off the same on everyones car, but the odometer is dead on. Why it is off is still a debate. I have GPS speed tracking on both my Escort 9500i radar and my VBOX Performance box and they are both in complete synch at all times. I would trust a GPS on the open road any day over a factory set speedo.
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06-20-2008, 02:00 PM | #8 | |
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I've got two GPS sources also (9500i and Garmin Nav). They both agree completely, and show that the speedo is off. I agree that it's more accurate than the speedo. From what I've read this is an issue on the 3 series as well. |
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06-20-2008, 02:51 PM | #10 | |
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Actually, I am pretty sure most cars from any maker are this way. I know my wife's Jeep is a few percent off and I have heard people talk about it on pretty much any car. Ther eis a regulation that saus the speedo cannot be more than a certain percentage low so they calibrate high. Also it helps with potential speeding tickes as you can;t go complain to the carmaker about it. |
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06-20-2008, 03:24 PM | #11 | ||
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If the OD is accurate (and it seems to be) then that means the error is in the output signal that drivers the speedometer. That's much better than the measurement itself being off. Quote:
My previous two cars (GTO and a GTI) were both off less than 1MPH. I don't think 3MPH is a huge issue, but it's just a lot for a car that's billed as a premium vehicle due to it's engineering. |
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06-20-2008, 04:36 PM | #12 |
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GROUP 62
Instruments B 62 02 96 Woodcliff Lake, NJ Product Engineering May 1996 SUBJECT: Maximum Permissible Speedometer Error MODELS: All General Information: A certain amount of "speedometer advance" is necessary to compensate for negative tolerances in tire diameter, electronic controls, and other factors. This advance reduces the risk of the speedometer displaying a speed that is less than the vehicle's actual speed. The amount of speedometer advance can be calculated by inputting a frequency (using the DIS Tester, "Kombi Test Schedule") that corresponds to a given speed and noting the speed that is indicated by the speedometer. The maximum permitted speedometer advance is 10% of the actual (input) speed plus 2.4 mph. Example: Actual Speed = 50 mph 50 mph x 10% = 5 mph; 5 mph + 2.4 mph = 7.4 mph Therefore, the permissible displayed speed is 50 to 57.4 mph. (Note: The displayed speed must never be less than the actual speed). No repairs should be attempted if the speedometer advance is within 10% + 2.4 mph. NOTE: The amount of speedometer advance has no effect on recording of accumulated mileage in the odometer display. The odometer records total mileage digitally and does not incorporate any "advance" tolerances. |
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06-20-2008, 08:29 PM | #13 |
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Thank you Mad Dragon, do you think my dealer would deny recalibration then? I really hate it reading fast, just like I hate when people set their clocks fast => ADJUST YOUR LIFE NOT YOUR CLOCK! It is one of those odd pet peaves of mine.
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06-20-2008, 08:39 PM | #15 |
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If my car is going 57mph and my cluster is reading 60mph in my opinion (the owner) there is something wrong with my cluster. I know that this is the acceptable range and how the powers that be intended it, but I like to have my gauges read as closely to correct as they are able to.
I appologize as what I was asking wasn't all that clear, according to your previous post it makes it seem like BMW AG/NA will not allow my dealer to change the speedometer to be exact if it is within the tollerance. Is that an accurate assumption?
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06-20-2008, 09:11 PM | #16 |
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I really wouldnt trust the GPS. There are a lot of factors involved in the accuracy of the GPS location, including the GPS module and the software that reads the GPS.
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06-20-2008, 09:32 PM | #17 |
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Ironically enough, I trust GPS with my life and the lives of others. But they are different systems I just thought that comment was ironic.
The speedo being off is not only a gps thing but also from several speed traps. Actually the gps might read 1mph fast or so as well.
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06-20-2008, 10:17 PM | #19 |
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06-20-2008, 10:46 PM | #20 |
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Presumably you people know that the BMW diagnostics will give you the real speed. If you don't know, look at the link below, use the secret menu screen to bring up option 8.0, and check it against GPS, I find it is withing 1kmph on my e90 323i. The speedo is set off on purpose to convice you you're travelling faster than you are. They're saving you some pocket money !!! This is also relevant in 0-60 Mph tests, you will need a couple of .'s extra to get there.
http://e90.wetpaint.com/page/BC+hidden+menus?t=anon
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06-20-2008, 11:09 PM | #21 | |
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06-21-2008, 09:46 AM | #22 | |
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What law states that the speedometer should be 3MPH off? I don't care what you do for a living, that is misinformation. If you've got a source for this law, lets see it. They may be choosing to err on the side of caution, but they're certainly not required by law to do so, and the fact that they do it on every car still doesn't make it right. |
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