Speedo Reading

Ross Malmgren · 07-05-2022, 07:03 AM

Took my 1st long trip in the 540i, 5 hours to Charleston from Atlanta. I noticed my speedo read 2-3mph higher than my Waze app the whole ride. Last night I rode past a digital speed reader again my car was 2mph higher.

Is this usual? I was thinking my car has the 20" wheels and maybe it's not calibrated correctly but wanted to see if anyone has any thoughts before calling the dealer.

Thank you -

HighlandPete · 07-05-2022, 07:14 AM

Quote:

Originally Posted by Ross Malmgren

Took my 1st long trip in the 540i, 5 hours to Charleston from Atlanta. I noticed my speedo read 2-3mph higher than my Waze app the whole ride. Last night I rode past a digital speed reader again my car was 2mph higher.

Is this usual? I was thinking my car has the 20" wheels and maybe it's not calibrated correctly but wanted to see if anyone has any thoughts before calling the dealer.

Thank you -

Normal. BMW comply with regulations, where the speedo must not under read.

European legislation is strict (we've had over reading speedos for as long as I can remember), there is a formula which allows for quite a + tolerance. It has been posted in other topics on this subject.

Ross Malmgren · 07-05-2022, 07:17 AM

Quote:

Originally Posted by HighlandPete

Normal. BMW comply with regulations, where the speedo must not under read.

European legislation is strict (we've had over reading speedos for as long as I can remember), there is a formula which allows for quite a + tolerance. It has been posted in other topics on this subject.

Thank You Pete -

Warp Ten · 07-05-2022, 10:21 AM

My 2019 540xi reads 2 mph higher than the digital speed reader in a school zone near me. Don't know how accurate the reader is but it is consistent. Interestingly, the speedo on my 2016 Corvette Z06 reads only one mph higher. --Bob

Edit: The readings mentioned were at about 35 mph. As SteveinArizona notes below, the difference probably gets higher at higher speeds. --Bob

SteveinArizona · 07-05-2022, 11:11 AM

Quote:

Originally Posted by HighlandPete

Normal. BMW comply with regulations, where the speedo must not under read.

European legislation is strict (we've had over reading speedos for as long as I can remember), there is a formula which allows for quite a + tolerance. It has been posted in other topics on this subject.

The faster you go, the more the speedo errs (percentage of a higher speed creates a greater variation). Generally speaking...2 mph off at lower speeds and 3 mph off at higher speeds.

Rocket455 · 07-05-2022, 12:49 PM

Same here. I've noticed a consistent over-read of 2mph on my 2016 535i and my current 2020 M340i; both confirmed via radar, pace car and different GPS apps.

mercidar · 07-05-2022, 02:21 PM

As others have said, this is very normal for BMW. However, I had a loaner 2021 330i for a couple weeks and its speedo matched Waze and speed signs exactly. That was the first BMW I've ever driven that didn't over-read.

Qsilver7 · 07-05-2022, 05:51 PM

Ditto replies above...this is normal and this discussions goes back at least as long as I've owned a BMW (1986).

It is the ECE Regulation 39 that causes European vehicles speedometers to read like they do:

Joe-BMW33 · 07-05-2022, 07:21 PM

BMW has been 2-3 mph over for the last 50 years. By design.

jimk · 07-05-2022, 07:32 PM

I think you can code the speedo to read actual speed.

AP · 07-06-2022, 12:32 AM

It's accuracy presumably varies minutely with tyre wear as well, although probably imperceptible.( reducing diameter)

Joe-BMW33 · 07-06-2022, 06:29 AM

I like it being over calibrated. When I go past a cop in a speed trap doing 80 in a 65, it makes me feel better that it is really 77 and cops don't usually pull you over for 10ish miles over the limit.

07-05-2022, 07:03 AM	#1
Ross Malmgren New Member 45 Rep 28 Posts Drives: 2019 BMW 540i Join Date: Jun 2022 Location: Acworth, GA iTrader: (0)	Speedo Reading Took my 1st long trip in the 540i, 5 hours to Charleston from Atlanta. I noticed my speedo read 2-3mph higher than my Waze app the whole ride. Last night I rode past a digital speed reader again my car was 2mph higher. Is this usual? I was thinking my car has the 20" wheels and maybe it's not calibrated correctly but wanted to see if anyone has any thoughts before calling the dealer. Thank you -
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07-05-2022, 10:21 AM	#4
Warp Ten Captain 663 Rep 640 Posts Drives: 2019 BMW 540xi Join Date: Oct 2018 Location: Lake Bluff IL iTrader: (0)	My 2019 540xi reads 2 mph higher than the digital speed reader in a school zone near me. Don't know how accurate the reader is but it is consistent. Interestingly, the speedo on my 2016 Corvette Z06 reads only one mph higher. --Bob Edit: The readings mentioned were at about 35 mph. As SteveinArizona notes below, the difference probably gets higher at higher speeds. --Bob __________________ 2019 540xi M Sport, Carbon Black/Cognac, 2014 328xi, 2016 Corvette Z06; Previous:2010 BMW 535xi M Sp, 2008 335xi, 1998 M3 Sedan,1980 528i, 1977 320i, 1976 2002 Last edited by Warp Ten; 07-06-2022 at 09:59 AM..
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07-05-2022, 12:49 PM	#6
Rocket455 Grumpysaurus Rex 494 Rep 423 Posts Drives: 2022 M550i Join Date: Jan 2020 Location: San Diego, CA iTrader: (0) Garage List 1972 Firechicken [0.00] 1969 Toronado [0.00] 1970 Camaro [0.00]	Same here. I've noticed a consistent over-read of 2mph on my 2016 535i and my current 2020 M340i; both confirmed via radar, pace car and different GPS apps. __________________ “Science has made us gods even before we are worthy of being men.”
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07-05-2022, 02:21 PM	#7
mercidar New Member 15 Rep 18 Posts Drives: 2018 M550i Join Date: May 2021 Location: Vancouver iTrader: (0)	As others have said, this is very normal for BMW. However, I had a loaner 2021 330i for a couple weeks and its speedo matched Waze and speed signs exactly. That was the first BMW I've ever driven that didn't over-read.
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07-05-2022, 05:51 PM	#8
Qsilver7 Major General 4489 Rep 7,532 Posts Drives: F06 650ix GC / F15 X5 50i Join Date: Oct 2016 Location: Indiana, USA iTrader: (0)	Ditto replies above...this is normal and this discussions goes back at least as long as I've owned a BMW (1986). It is the ECE Regulation 39 that causes European vehicles speedometers to read like they do: Attached Images __________________ 2015 F06 650ix Gran Coupe`(Moonstone/Cohiba Brown)\| 2014 F15 X5 50i MSport (Space Gray/Mocha) Become a BMW CCA member! Click HERE to join and feel free to use my BMW CCA member #191509 as a referral.
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07-05-2022, 07:21 PM	#9
Joe-BMW33 Major General 7433 Rep 6,812 Posts Drives: '18 M550i\|'21 X5\|'03 540i Join Date: Apr 2021 Location: Boston iTrader: (1) Garage List 2013 VW Tiguan [0.00] 2015 Infiniti QX60 [0.00] 2021 BMW X5 [0.00] 2003 BMW 540i [0.00] 2018 BMW M550 [10.00]	BMW has been 2-3 mph over for the last 50 years. By design. __________________ 2018 M550ix\|Carbon Black\|Dinan Modifications\|2003 540i\|Jet Black\|M-Sport\|2021 X5 Mineral White Prior BMW's: 1987 325e\|1993 740i\|1998 740il\|2001 530i\|2002 745li\|2007 750li\|2006 750li\|2001 530i\|2012 535xi\|
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07-05-2022, 07:32 PM	#10
jimk Captain 106 Rep 935 Posts Drives: 2018 M550i Join Date: Jun 2009 Location: Camarillo, CA iTrader: (8)	I think you can code the speedo to read actual speed.
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07-06-2022, 12:32 AM	#11
AP Major General 2808 Rep 5,123 Posts Drives: G30 M550 Join Date: Apr 2011 Location: UK iTrader: (0)	It's accuracy presumably varies minutely with tyre wear as well, although probably imperceptible.( reducing diameter)
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07-06-2022, 06:29 AM	#12
Joe-BMW33 Major General 7433 Rep 6,812 Posts Drives: '18 M550i\|'21 X5\|'03 540i Join Date: Apr 2021 Location: Boston iTrader: (1) Garage List 2013 VW Tiguan [0.00] 2015 Infiniti QX60 [0.00] 2021 BMW X5 [0.00] 2003 BMW 540i [0.00] 2018 BMW M550 [10.00]	I like it being over calibrated. When I go past a cop in a speed trap doing 80 in a 65, it makes me feel better that it is really 77 and cops don't usually pull you over for 10ish miles over the limit. __________________ 2018 M550ix\|Carbon Black\|Dinan Modifications\|2003 540i\|Jet Black\|M-Sport\|2021 X5 Mineral White Prior BMW's: 1987 325e\|1993 740i\|1998 740il\|2001 530i\|2002 745li\|2007 750li\|2006 750li\|2001 530i\|2012 535xi\|
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