[eltonc]

I have an E91 and recently noticed and verified (via GPS) that the speedometer was of by about 5 mph. When I went in for service I asked them to take a look at the speedometer since it was of. The service guy told me that they are aware of this and BMW sent them a notice that it is to be expected. Something to do with calibration, etc.

So in short I was told there was nothing wrong with it. I disagree since I paid good money for this car and isn't a cheap car. If the speedometer is of, this would mean the gas mileage probably won't be accurate. Ihave never heard of a car that should have an inaccurate speedometer.

Has anyone else checked to see if their speedometer is reading properly?

[pmeloche]

Both my X5 and my Z4MC show a 3~4 mph difference between the speedometer and the GPS-calculated speed.

[Citizen Z]

All 1er speedos are all off by about 5%, on the optimistic side. Every single one. Its a design/safety decision made by BMW for liability reasons, not a design or mechanical fault.

[eltonc]

Thanks for confirming. I wasn't sure if this was isolated to the 3 series.

I've never heard of actually doing this on purpose for safety reasons. Until I found out it's of, I guess I was driving 5 pmh slower than I expected.

[135i_TT]

VW Jettas had that problem as well.... Speedo would redline at 130mph but the actual top speed is 128mph..

[Citizen Z]

Originally Posted by 135i_TT

VW Jettas had that problem as well.... Speedo would redline at 130mph but the actual top speed is 128mph..

I've GPS verified the 135i is only actually doing about 148 when it tops out at indicated 155mph. Yes, 7mph difference. Put 225/40's on the front and 265/35's on the back and you should be able to reclaim some if not all of that speed differential.

[NYSPEM3]

Originally Posted by eltonc

I have an E91 and recently noticed and verified (via GPS) that the speedometer was of by about 5 mph. When I went in for service I asked them to take a look at the speedometer since it was of. The service guy told me that they are aware of this and BMW sent them a notice that it is to be expected. Something to do with calibration, etc.

So in short I was told there was nothing wrong with it. I disagree since I paid good money for this car and isn't a cheap car. If the speedometer is of, this would mean the gas mileage probably won't be accurate. Ihave never heard of a car that should have an inaccurate speedometer.

Has anyone else checked to see if their speedometer is reading properly?

This can't be Real, can it?

[sailvi767]

Almost all cars will show a large speedo air at high speeds. This is because the tires grow in diameter when you start pushing a car above 100 mph. My 335I is 2 to 3 mph off at 70.

[JackMac]

Ever wonder if BMW will fix it?

Seriously, all BMW spedo's perform this way, for several generations now. Your dealership is correct.

[canucklion]

that's blasphemy, next thing you're going to tell me earth is round when in fact it's flat!!!

speedometer off

Measured speedometer error using GPS

BMW speedometer way optimistic

Speedometer Accuracy Issue

Speedometer shows 5 mph higher than real speed

E90 Speedometer error

speedometer accuracy vs GPS

This is probably due to speedometer error right?

Speedometer accuracy

Proof that the Speedometer is inaccurate

BMW Speedometer Incorrect - Myth TESTED and ANSWERED

Question about Speedometer Accuracy

Speedometer off

Originally Posted by eltonc

I have an E91 and recently noticed and verified (via GPS) that the speedometer was of by about 5 mph. When I went in for service I asked them to take a look at the speedometer since it was of. The service guy told me that they are aware of this and BMW sent them a notice that it is to be expected. Something to do with calibration, etc.

So in short I was told there was nothing wrong with it. I disagree since I paid good money for this car and isn't a cheap car. If the speedometer is of, this would mean the gas mileage probably won't be accurate. Ihave never heard of a car that should have an inaccurate speedometer.

Has anyone else checked to see if their speedometer is reading properly?

[hanmaas]

There's nothing wrong with it, it's like that on Purpose.

[demosthenes]

I compared Car&Driver's "MPH per 1000 RPM" numbers from their January 2008 328i comparison test

(http://www.caranddriver.com/reviews/comparison_test/sedans/2007_bmw_328i_vs_2008_cadillac_cts_di_2008_m_b_c30 0_sport_2008_infiniti_g35_sport_comparison_test)

to my indicated speeds in gears. I noticed a variation ranging from 2 mph in 1st gear to 4 mph in 6th (6MT). My experiences with stationary radar-based speed detectors has been consistent with that.

[maraud]

Originally Posted by Citizen Z

All 1er speedos are all off by about 5%, on the optimistic side. Every single one. Its a design/safety decision made by BMW for liability reasons, not a design or mechanical fault.

There isn't a car out there (in all likelyhood) that has a speedo which is 100% accurate. However, 5% is a bit much and in the manufacurers best interest - not ours for "safety". Think of it like this: if your car always shows you going 5% faster than you actually are, you will be racking up miles faster as well, thus burning through warranty faster. Over the life of the factory warranty you'd actually losed 2500 miles of coverage.

[Tonybest]

The speedOmeter is off by 5 - 6 km/h on my car... also checked with GPS. But the odometer is right on the money... checked with GPS also. So I think I'm driving faster than I really am (less speeding tickets) and my resale value is not altered for extra mileage... So no harm done... So it's a good thing in my case.

[mike-y]

all cars are like this to some degree. My acura was off 2-3mph at 80 compared to the GPS. also as tires wear, their rolling circumference gets smaller, causing the speed to read a bit higher than when the tire was new.

I don't know how to make a large "s", so imagine it.

[kgb1637]

Nearly every has this built in, most are about 3-5 mph off. I did a physics project that proved this much to the dismay of my professor. Also, how accurate is your GPS speed, thats another thing to look at.

[ettil]

Originally Posted by canucklion

that's blasphemy, next thing you're going to tell me earth is round when in fact it's flat!!!

Ten's of thousands of previous inaccurate speedometer threads removed for brevity.

Ahhhh I needed that! Thank you!

And this thread was the best reminder of why I abandoned the General forum...

But seriously, it's very rare and unusual but you too can use "search" and find out many many many amazing things. Do not be afraid of it.

[blakjack23]

Wow, I've never heard of thiS

[boogiee90]

Yeah my 06 E90's speedometer reads 4mph less than what the gps is giving me. I think its a good thing cause if you get pulled over for speeding, then you can tell the officer that you were actually running 4mph slower... LOL.

[Tallest]

its not a 'problem'. This is intended. To keep your arse safe. Fuel consumption indicators are very accurate in my experience btw. Just dont believe the official figures.

[kgb1637]

Originally Posted by boogiee90

Yeah my 06 E90's speedometer reads 4mph less than what the gps is giving me. I think its a good thing cause if you get pulled over for speeding, then you can tell the officer that you were actually running 4mph slower... LOL.

Unfortunately if you get pulled over those radar guns are VERY accurate. Thats why when you drive by those "Your Speed" things it says its lower than your speedo.

[Orient330iNYC]

this topic has been beaTen to death. its by design.
EU law requires that a speedometer never, ever read lower than actual ground speed. BMW and other bias the speedometer DISPLAY upward by about 5% to account for all the various tire sizes that could be put on a car. the actual speed recorded by the ecu is unbiased so odometer readings are accurate.