speedometer accuracy vs GPS

southern drawl · 06-23-2007, 12:01 PM

Howdy all, my 06 325i has built in GPS, but many times I use my Garmin portable gps instead because it has lots of points already programmed in. When the car speedometer shows I'm doing 65 mph, the Garmin will consistently show 61 or 62 mph. I'm using 65 mph just as an example. The same rough difference occurs at other speeds

If this proves the car's speedometer is in accurate, I'm concerned because I'd like it to be accurate, and I feel it would unfairly shorten my warranty period. I will check with the dealer, but do you know what is involved in recalibrating the speedometer for accuracy? Your thoughts appreciated.
Thanks,
SD

dcar335i · 06-23-2007, 12:34 PM

I see the same with my 335i and on my previous '02 330I - speedo reading 2-3 MPH high. It is evident when my speedo reads 78 in a 70 and I am getting passed right and left. Portable GPS confirmed for me as well.

I understand your concern about shortened warranty period but wonder if the speedo is directly linked to the odometer as older mechanical systems used to be. Mabe it's possible for the odometer to be accurate and the speedo be calibrated 2 MPH high?

AndreTheGeek · 06-23-2007, 01:23 PM

There are several threads on this already if you search.
The BMW speedometers do read high.

MikeCCrutchfield · 06-23-2007, 02:04 PM

Quote:

Originally Posted by southern drawl

Howdy all, my 06 325i has built in GPS, but many times I use my Garmin portable gps instead because it has lots of points already programmed in. When the car speedometer shows I'm doing 65 mph, the Garmin will consistently show 61 or 62 mph. I'm using 65 mph just as an example. The same rough difference occurs at other speeds

If this proves the car's speedometer is in accurate, I'm concerned because I'd like it to be accurate, and I feel it would unfairly shorten my warranty period. I will check with the dealer, but do you know what is involved in recalibrating the speedometer for accuracy? Your thoughts appreciated.
Thanks,
SD

Analog Speedometer on dash=HIGH
odometer/Speedometer in computer=pretty damn close to perfect
get over it, move on.

shocka1212 · 06-23-2007, 02:09 PM

mine is off by 4mph. when it reads 65, im only doing 61

Nyulak · 06-23-2007, 07:36 PM

Mine reads 152 when the Garmin states 144.

I want my 8 MPH!

06-23-2007, 12:01 PM	#1
southern drawl New Member 1 Rep 13 Posts Drives: 06 325i Black Join Date: May 2006 Location: Richmond, Va. iTrader: (0)	speedometer accuracy vs GPS Howdy all, my 06 325i has built in GPS, but many times I use my Garmin portable gps instead because it has lots of points already programmed in. When the car speedometer shows I'm doing 65 mph, the Garmin will consistently show 61 or 62 mph. I'm using 65 mph just as an example. The same rough difference occurs at other speeds If this proves the car's speedometer is in accurate, I'm concerned because I'd like it to be accurate, and I feel it would unfairly shorten my warranty period. I will check with the dealer, but do you know what is involved in recalibrating the speedometer for accuracy? Your thoughts appreciated. Thanks, SD
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06-23-2007, 12:34 PM	#2
dcar335i Private 0 Rep 59 Posts Drives: 335i Join Date: Mar 2007 Location: Michigan iTrader: (0)	I see the same with my 335i and on my previous '02 330I - speedo reading 2-3 MPH high. It is evident when my speedo reads 78 in a 70 and I am getting passed right and left. Portable GPS confirmed for me as well. I understand your concern about shortened warranty period but wonder if the speedo is directly linked to the odometer as older mechanical systems used to be. Mabe it's possible for the odometer to be accurate and the speedo be calibrated 2 MPH high?
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06-23-2007, 01:23 PM	#3
AndreTheGeek Lieutenant 16 Rep 463 Posts Drives: 335i E90 Alpine White Join Date: Feb 2007 Location: Ottawa, Canada iTrader: (0)	There are several threads on this already if you search. The BMW speedometers do read high.
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06-23-2007, 02:09 PM	#5
shocka1212 Philanthropist 28 Rep 1,054 Posts Drives: e92 Join Date: Jan 2006 Location: NJ iTrader: (1)	mine is off by 4mph. when it reads 65, im only doing 61
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06-23-2007, 07:36 PM	#6
Nyulak Captain 29 Rep 957 Posts Drives: 2022 X3 M40i Join Date: Feb 2007 Location: SheffVill, OH iTrader: (4) Garage List 2009 BMW 535xi [10.00]	Mine reads 152 when the Garmin states 144. I want my 8 MPH!
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