E90Post
 


N54Tuning.com
 
BMW 3-Series (E90 E92) Forum > BMW E90/E92/E93 3-series General Forums > General E90 Sedan / E91 Wagon / E92 Coupe / E93 Cabrio > BMW Intentionally Gives Us Inaccurate Speedometers!



Reply
 
Thread Tools Search this Thread
      02-16-2006, 12:09 PM   #23
sdorn
Lieutenant
sdorn's Avatar
6
Rep
491
Posts

 
Drives: 2006 Jet Black 325i
Join Date: Feb 2006
Location: Atlanta

iTrader: (0)

Quote:
Originally Posted by E90Fleet
Our local car magazine uses a calibrated wheel that is attached to the car to detemine speedo accuracy, and I can tell you there isnt 1 car that is 100% accurate, no matter what the make

1 or 2 cheap makes overread soometimes, but the rest always underread.


Also you can have a 100% accurate spedo on 1 set of tires,but wear those tires down a bit or change to a different make of tires and the reading will be different
100% accuracy isn't expected, but 99% accuracy is expected and would be acceptable. 92% - 94% accuracy is unacceptable.
__________________
2008 Sparkling Graphite 535i
2009 Land Rover LR2
2003 Porsche 911 Turbo (SOLD)
2006 Jet Black 325i (SOLD)
2001 Bullitt Mustang (450rwhp - SOLD)
Appreciate 0
      02-16-2006, 12:10 PM   #24
fletcher969
Dad: "Can't never did nothing"
fletcher969's Avatar
5
Rep
319
Posts

 
Drives: '96 Camaro
Join Date: Nov 2005
Location: Chicago, IL

iTrader: (0)

Is there not a way for the dealer to program the speedo so it's at least "more" accurate? I too have had numerous "cheaper" cars, and they all were dead on using the "scientific" 60 second/mile test. Even the old crapper Ford Escort I had years ago (may it RIP - frame snapped by the firewall...what an amazing experience driving a car that semi-buckles when you shift!!!)! For me it's just a matter of something being accurate when arguably that is the premise on which it was invented anyway...accurate disclosure of one's speed. I'll no doubt make the adjustments in my head, and memorize them, but I shouldn't have to do that on any vehicle so equipped, expensive or not. In time it will be less of an issue for me as the numbers in my head become second nature, but I'd think if BMW can provide other features of the car that are unique to the various markets it serves (most notable - clear vs amber corners), I would think it could also provide a speedo to comsumers in this market that is as accurate as we are accustomed to. Oh well...regardless, I can't wait for my car to arrive in a few weeks so I can go out and figure out the "actual vs displayed" speed chart!
__________________
2006 330i: SG/Blk-Blk-Burl/6MT/ZSP/Heated seats/Sat prep
01-26-2006: Ordered Vehicle
02-01-2006: Production Start
02-06-2006: Production End
02-09-2006: Arrived at POExit
02-13-2006: Transit - Don Juan
03-01-2006: Unloaded in Charleston
03-02-2006: VPC
03-06-2006: Arrived at dealership
03-08-2006: Took delivery
Appreciate 0
      02-16-2006, 12:16 PM   #25
sdorn
Lieutenant
sdorn's Avatar
6
Rep
491
Posts

 
Drives: 2006 Jet Black 325i
Join Date: Feb 2006
Location: Atlanta

iTrader: (0)

Quote:
Originally Posted by fletcher969
Is there not a way for the dealer to program the speedo so it's at least "more" accurate?
They claim they can't adjust it. I think you could probably put bigger tires on it which would offset the inaccuracy.
__________________
2008 Sparkling Graphite 535i
2009 Land Rover LR2
2003 Porsche 911 Turbo (SOLD)
2006 Jet Black 325i (SOLD)
2001 Bullitt Mustang (450rwhp - SOLD)
Appreciate 0
      02-16-2006, 12:19 PM   #26
epiphone3
Lieutenant Colonel
27
Rep
1,647
Posts

 
Drives: 2013 BMW X3 35i
Join Date: Oct 2005
Location: Calgary

iTrader: (0)

If the speedo error that is intentionally built in stops you from buying another BMW, you have other issues....
Appreciate 0
      02-16-2006, 12:29 PM   #27
jcoo085
Lieutenant
jcoo085's Avatar
10
Rep
463
Posts

 
Drives: E90 320d
Join Date: Sep 2005
Location: Stuttgart, Germany

iTrader: (0)

Garage List
2005 320d  [0.00]
Every single car I have ever owned has undervalued the speed. The speedometer is designed that way. It's an insurance buffer.

Imagine if every time you changed tyres or added aftermarket wheels you also had to recalibrate the speedometer. Why do you think the police vehicles need to have their speedometers recalibrated regularily?

Imagine if BMW made a speedometer that might, in certain circumstances (with, say, aftermarket wheels), overvalue the speed. Then imagine people were getting ticketed. BMW would be able to hear the class action calls all the way across the Atlantic!

That said, my speedometer is pretty accurate, according to one of those speed displays they have set up on one of the roads here in Stuttgart. When the needle is pointing at 50km/h, the sign reads between 47 and 49. But NEVER 50.

Also and out of interest, I believe that the speed display that is accessible in the hidden OBC menu is accurate. Or maybe not...

Finally, the speed isn't read from the transmission as one poster mentioned. I actually found that it is read from the rear wheels. About a month ago the street into my driveway was completely iced over. Coupled with the fact that it is on an incline and it's very difficult to get momentum out of the gate, I had to turn DSC completely off and allow the car to spin itself forward. While the wheels were spinning, the speedo was going up and down like a yoyo.

This is first time ever that I have heard someone complain that their speedometer shows a higher speed than they are actually travelling. It boggles the mind.
__________________

E90 320d - Black Ext/Fluid Grey Int | Steptronic | Business Navigation | PDC | Sunroof | Alarm
Exterior Pictures | Interior Pictures | Video
Appreciate 0
      02-16-2006, 12:33 PM   #28
Broken1
E90 Addict
Broken1's Avatar
South Africa
52
Rep
2,040
Posts

 
Drives: E90 325i Sparking Graphite
Join Date: May 2005
Location: Johannesburg

iTrader: (0)

Garage List
***HINT!!!***

If you set your cruise control, and then RESET your average speed; your car will show you your exact speed read off the abs sensors. It has been tested by someone I know with a radar gun. The OBC said 127.2km/h and he clocked in at 127.5km/h.

Also, there is a hidden menu in the car - with the option to see the exact speed, and the indicated speed. Indicated speed is optimistic. Search for threads on this hidden menu...
"08.00 V-EFF = exact speed
08.01 V-ANZ = "Anzeige" speed shown on dash.."
http://www.e90post.com/forums/showth...ht=hidden+menu
Appreciate 0
      02-16-2006, 12:40 PM   #29
imageWIS
Audi Roamer…
imageWIS's Avatar
3
Rep
221
Posts

 
Drives: 06' Audi A4 2.0T
Join Date: Feb 2006
Location: Boca Raton, FL

iTrader: (0)

Send a message via AIM to imageWIS
Smile

Quote:
Originally Posted by ward
also the fuel gauge is pessimistic
Sounds like Audi…

Jon.
__________________
Die Gedanken sind frei

Sucker love is heaven sent.
You pucker up, our passion’s spent.
My hearts a tart, your body’s rent.
My body’s broken, yours is spent.
Appreciate 0
      02-16-2006, 12:47 PM   #30
330m
First Lieutenant
330m's Avatar
England
3
Rep
364
Posts

 
Drives: 330i
Join Date: Feb 2006
Location: Manchester

iTrader: (0)

There seem to be a confusion here between understanding of 'over reading' and 'under reading'.

For sure ALL vehicle speedos must over read by law. i.e. it must indicate a faster speed than you are actually travelling at so you can not accidentally go too fast.

I looked into this for a UK audi forum before and basically the European speed indication specification is a maximum error of +5% -0% (of full scale) and an additional error of +10mph (at any point on the range)

So your speedo could read 10mph when you were stationary and still be in specification!!!

I've done a few tests with my GPS based speed trap detector which has a very accurate speed measurement display and for sure the car always over reads.

At 70mph on the GPS the car is reading 74mph.

At 100mph on the GPS the car is reading 106mph

Even hot or cold tyres make a slight difference.
Appreciate 0
      02-16-2006, 12:57 PM   #31
espo
Captain
espo's Avatar
United_States
7
Rep
718
Posts

 
Drives: 2014 M235i
Join Date: Sep 2005
Location: Sugar Land TX

iTrader: (0)

It's a CYA (Cover your a**) problem. If anybody in the US could show that the speedo was underestimating the speed of the car (no matter what tires were on it), then BMW could and probally would be sued and/or fined. American car makes get much more leway with things like this, so there speedo's are going to be more accurate.

If your really that pissed off about it... Here is a place that will re-calibrate it for you (if you want to drive to Richmond):

http://www.speedotest.com/
__________________
E46 325xi Oxford Green/Sand Leatherette/Myrtle Wood Auto ZCW - Retired
E90 330xi Mystic Blue/Black Leather/Aluminum 6sp Manual ZSP/ZPP/ZCW/CA - Retired
F22 M235i Mineral Gray/Red Leather/Aluminum 6sp Manual ZPP/ZTP
Appreciate 0
      02-16-2006, 01:28 PM   #32
E90Fleet
Major General
South Africa
157
Rep
8,098
Posts

 
Drives: BMW
Join Date: Apr 2005
Location: South Africa

iTrader: (0)

Just checked it up in the issue of our local car magazine where they tested the 320d with 16" wheels

According to equipment calibrated by our standards authority the speedo was underreading by 1.2%, well within the difference tires can make


You can also change your reading with your tire pressures, though not as much with the runflats, but it will still make a difference
__________________
Nominated: Member of the Year, Most Contributing Member


BMW if you are reading, I need a job
Appreciate 0
      02-16-2006, 03:59 PM   #33
Carnage
Lieutenant General
Carnage's Avatar
United_States
180
Rep
16,404
Posts

 
Drives: people insane
Join Date: Jun 2005
Location: classified

iTrader: (2)

Mine is off by about 1 mph when I checked it in comparsion to my GPS over the summer. To me it's means it's close to dead on, seeing as how GPS can be slightly off. When I was going 70 the GPS would show I was going 71.
Appreciate 0
      02-16-2006, 04:09 PM   #34
330m
First Lieutenant
330m's Avatar
England
3
Rep
364
Posts

 
Drives: 330i
Join Date: Feb 2006
Location: Manchester

iTrader: (0)

Coming from a background in mechical instrumentation, even a 5% tolerance is tight for a mass produced pointer instrument. The GPS is better than 1% error which is better than all but a reference mechanical instrument. Every part of the speedo system has a tolerance on it, The tyre tread, tyre pressure, wheel speed sensor, dash controller, pointer drive mechanism etc etc....

So +5% Full scale on a clock that shows 170mph is +8.5mph acceptable error at any speed. There is no need for them to be accurate, only to ensure you don't go faster than indicated. If it reads 60 when you're doing 50, whats the problem? except you'd pi## of other drivers. Your not going to break any laws or be able to sue anyone!!

It MUST OVER READ (show faster than actual speed)

Anyones speedo that UNDER READS (shows less than actual speed) is plainly dangerous and probably illegal for sure!!
Appreciate 0
      02-16-2006, 04:38 PM   #35
Garrett
Banned
16
Rep
1,356
Posts

 
Drives: 2004 330ci
Join Date: Nov 2005
Location: Mich

iTrader: (0)

Quote:
Originally Posted by sdorn
I know this is common knowledge for many BMW owners, but I just realized that it is true! I bought my first BMW two weeks ago, and I immediately noticed something was wrong with the speedometer. I had a friend pace me to confirm it, then I took my GPS to find out exactly how far off it was. I found that when the speedometer says 55mph, the GPS said 52mph. With the cruise on 80mph, the GPS read 75 or 76mph.

I took the car in to the dealer today to get satellite radio installed and get the Bluetooth software upgraded, I told them about the problem. They said it was normal and there was nothing wrong with it! He had like a 3 minute long speech about how it was safer and tire circumferences change and blah blah blah. I had read it all on the internet before. He even said that every BMW on the road has this error intentionally built in! I can't believe a $40k car that is supposed to be a precision driving machine has one of the most key instruments on the machine off by such a huge margin.

We need to start a campaign to get BMW to address this issue. If all the members of this board and any other boards we can get to participate suddenly started taking their cars into their dealers to complain about the speedometers, that would cause a huge backlash at BMW. It might be enough to get them to fix the problem. Sending letters to BMW would also be a great idea, like one every week.

This really irritates me. It might just keep me from buying another BMW. I am seriously thinking about buying an aftermarket navigation system just so I can have an accurate speedometer. I even looked into the lemon laws here in the state to see if it applies in this situation. I would have to argue that it is a serious safety hazard to have an inaccurate speedometer, which is a plausible argument. I did some legal research, but I couldn't find any lawsuits involving this type of situation.

My Chevrolet does the same.
Appreciate 0
      02-16-2006, 04:54 PM   #36
sdorn
Lieutenant
sdorn's Avatar
6
Rep
491
Posts

 
Drives: 2006 Jet Black 325i
Join Date: Feb 2006
Location: Atlanta

iTrader: (0)

Quote:
Originally Posted by matsarge
Mine is off by about 1 mph when I checked it in comparsion to my GPS over the summer. To me it's means it's close to dead on, seeing as how GPS can be slightly off. When I was going 70 the GPS would show I was going 71.
If mine was that close I wouldn't be upset.

Quote:
Originally Posted by 330m
Your not going to break any laws or be able to sue anyone!!
Actually, just the fact that it is inaccurate could be grounds for a lawsuit under the right circumstances. I could imagine a situation where going too slow could cause an accident or contribute to one. Here in Ga, you can get a ticket for going too slow as well. There are minimum speed limits that, in theory, you could violate. If someone wasn't aware of the inaccuracy of the speedometer and relied in good faith on its readings, BMW could have some liability.

The real liability would be if the odometer was similarly inaccurate. There would be a huge class action group of people that paid mileage overcharges on leases that could sue. There would be another huge group of people who were denied warranty coverage because they were just over the warranty mileage as a result of the inaccurate odometer.

This is all theoretical, though. I just want my damn speedometer fixed.
__________________
2008 Sparkling Graphite 535i
2009 Land Rover LR2
2003 Porsche 911 Turbo (SOLD)
2006 Jet Black 325i (SOLD)
2001 Bullitt Mustang (450rwhp - SOLD)
Appreciate 0
      02-16-2006, 04:59 PM   #37
e90fanatic
Absolute0
e90fanatic's Avatar
No_Country
71
Rep
5,018
Posts

 
Drives: Has a Roundel
Join Date: Apr 2005
Location: TO/HK/NJ

iTrader: (6)

Garage List
2006 330i  [0.00]
Send a message via AIM to e90fanatic
i heard it was a regulation for cars now. My previous S60's speedo was intentionally 10% faster.
__________________
To procede or not to procede......
Appreciate 0
      02-16-2006, 05:00 PM   #38
e90fanatic
Absolute0
e90fanatic's Avatar
No_Country
71
Rep
5,018
Posts

 
Drives: Has a Roundel
Join Date: Apr 2005
Location: TO/HK/NJ

iTrader: (6)

Garage List
2006 330i  [0.00]
Send a message via AIM to e90fanatic
US is less but my previous car was Canadian and they require more.
__________________
To procede or not to procede......
Appreciate 0
      02-16-2006, 05:16 PM   #39
sdorn
Lieutenant
sdorn's Avatar
6
Rep
491
Posts

 
Drives: 2006 Jet Black 325i
Join Date: Feb 2006
Location: Atlanta

iTrader: (0)

I found an article from Car and Driver that I remember reading several years ago. It explains the reasons for inaccurate speedometers and identifies BMW as the worst of all brands, by far. Also, here in the US there appears to be no law requiring speedometers to always show high. There is a regulation requiring this in the EU, but not as much error as BMW puts in. Here is the article:

Speedometer Scandal!
Can you trust your most frequently consulted gauge?
BY FRANK MARKUS
April 2002

Regular readers have probably noticed that when we describe a vehicle that really gets our juices flowing, we tend to hyperbolize about the accuracy and precision with which the steering wheel and pedals communicate exactly what is happening down where the rubber meets the road. It has recently come to our attention, however, that many of the cars we like best are surprisingly inaccurate about reporting the velocity with which the road is passing beneath the tires. Or, to put it another way, speedometers lie.

Yes, ladies and germs, we are scooping 20/20 and 60 Minutes with this scandal: Speedometers Lie! Okay, "exaggerate" may state it more aptly, if less provocatively.

When traveling at a true 70 mph, as indicated by our highly precise Datron optical fifth-wheel equipment, the average speedometer (based on more than 200 road-tested vehicles) reads 71.37 mph. Wait, wait! Before you roll your eyes and turn the page, let us dig just a bit deeper and reveal some dirt.

Sorted by price, luxury cars are the least accurate, and cars costing less than $20,000 are the most accurate. By category, sports cars indicate higher speeds than sedans or trucks. Cars built in Europe exaggerate more than Japanese cars, which in turn fib more than North American ones. And by manufacturer, GM's domestic products are the most accurate, and BMW's are the least accurate by far. One other trend: Only 13 of our 200 test speedos registered below true 70 mph, and only three of those were below 69 mph, while 90 vehicles indicated higher than 71 mph. Are our cars trying to keep us out of traffic court?

To understand, let's first study the speedometer. In the good old days, plastic gears in the transmission spun a cable that turned a magnet, which imparted a rotational force to a metal cup attached to the needle. A return spring countered this force. Worn gears, kinked or improperly lubed cables, tired springs, vibrations, and countless other variables could affect these mechanical units.

But today, nearly all speedometers are controlled electronically. Typically, they are driven by either the vehicle's wheel-speed sensors or, more commonly, by a "variable reluctance magnetic sensor" reading the speed of the passing teeth on a gear in the transmission. The sine-wave signal generated is converted to speed by a computer, and a stepper motor moves the needle with digital accuracy.

Variations in tire size and inflation levels are the sources of error these days. Normal wear and underinflation reduce the diameter of the tire, causing it to spin faster and produce an artificially high reading. From full tread depth to baldness, speeds can vary by up to about two percent, or 1.4 mph at 70 mph. Lowering tire pressure 5 psi, or carrying a heavy load on the drive axle, can result in about half that difference. Overinflation or oversize tires slow down the speedometer. All our speed measurements were made on cars with new stock tires correctly inflated, but one might expect a manufacturer to account for wear and to bias the speed a bit low; results suggest that not to be the case.

So we sought out the rule book to find out just how much accuracy is mandated. In the U.S., manufacturers voluntarily follow the standard set by the Society of Automotive Engineers, J1226, which is pretty lax. To begin with, manufacturers are afforded the latitude to aim for within plus-or-minus two percent of absolute accuracy or to introduce bias to read high on a sliding scale of from minus-one to plus-three percent at low speeds to zero to plus-four percent above 55 mph. And those percentages are not of actual speed but rather a percentage of the total speed range indicated on the dial. So the four-percent allowable range on an 85-mph speedometer is 3.4 mph, and the acceptable range on a 150-mph speedometer is 6.0 mph.

But wait, there's more. Driving in arctic or desert climates? You're allowed another plus-or-minus two percent near the extremes of 20-to-130-degrees Fahrenheit, and yet another plus-or-minus one percent if the gauge was ever exposed to minus-40 to plus-185 F. Alternator acting up? Take another plus-or-minus one percent if the operating voltage strays two volts above or below the normal rating. Tire error is excluded from the above, and odometer accuracy is more tightly controlled to plus-or-minus four percent of actual mileage.

The European regulation, ECE-R 39, is more concise, stating essentially that the speed indicated must never be lower than the true speed or higher by more than one-tenth of true speed plus four kilometers per hour (79.5 mph at a true 70). Never low. Not even if somebody swaps a big set of 285/35R-18s for stock 255/45R-16s.
There's your explanation of high-reading European speedometers, with the highest readings on Porsches and BMWs that are most likely to lure owners inclined to fool with tire sizes. Of course, only the speedometer must conform. Trip computers are free to report average speed honestly. Try setting your BMW or Porsche cruise control and then resetting the average-speed function. Unless you've screwed up the tires, the trip computer should show a nearly accurate reading. Even General Motors, whose domestic speedometers are the best, must skew its readings slightly high on vehicles exported to Europe.

So there you have it: the raw, unvarnished truth about speedometers, laid bare without the underhanded aid of secret pyrotechnics. Readjust your comfortable indicated cruising speeds accordingly.

__________________
2008 Sparkling Graphite 535i
2009 Land Rover LR2
2003 Porsche 911 Turbo (SOLD)
2006 Jet Black 325i (SOLD)
2001 Bullitt Mustang (450rwhp - SOLD)
Appreciate 0
      02-16-2006, 05:28 PM   #40
dkizerian
Digital Ruler
1
Rep
166
Posts

 
Drives: 325i AW/Terra
Join Date: Oct 2005
Location: Riverton Utah

iTrader: (0)

Make sure you don't buy any of the following vehicles as I've had experiences with their speedometers/odometers being off

Ford focus
Ford f250
dodge ram 2500
toyota 4-runner
toyota corolla
VW gti
Audi a4
audi allroad
Volvo cross country
subaru impreza
acura integra
nissan 240sx
Appreciate 0
      02-16-2006, 05:31 PM   #41
dkizerian
Digital Ruler
1
Rep
166
Posts

 
Drives: 325i AW/Terra
Join Date: Oct 2005
Location: Riverton Utah

iTrader: (0)

your post from car and driver made me remember the following cars too.

Honda civic
Honda accord
jeep wrangler
jeep cherokee
Appreciate 0
      02-16-2006, 05:51 PM   #42
SteveMD
Colonel
SteveMD's Avatar
United_States
48
Rep
2,431
Posts

 
Drives: '12 X5 50i, '11 GTI DSG
Join Date: Dec 2005
Location: Raventown!

iTrader: (3)

Garage List
2012 X5 50i  [0.00]
I'm not buying another BMW. Yesterday I set the heat to 80 and when I measured it with my NIST calibrated thermocouple in four random locations, front and rear, it was only 79.4 degrees.

I'm pissed!
__________________
2006 E90 330i (retired)
2009 E90 335i (retired)
2012 E70 X5 50i M Sport, JB Stage 1, 4.6 secs 0-60.
2011 VW GTI/DSG
Appreciate 0
      02-16-2006, 05:55 PM   #43
JackMac
Recovering BMW Addict
JackMac's Avatar
Scotland
35
Rep
1,920
Posts

 
Drives: <OO (|||)(|||) OO>
Join Date: Nov 2005
Location: Southeast PA

iTrader: (7)

Garage List
Appreciate 0
      02-16-2006, 07:05 PM   #44
Carnage
Lieutenant General
Carnage's Avatar
United_States
180
Rep
16,404
Posts

 
Drives: people insane
Join Date: Jun 2005
Location: classified

iTrader: (2)

Quote:
Originally Posted by SteveMD
I'm not buying another BMW. Yesterday I set the heat to 80 and when I measured it with my NIST calibrated thermocouple in four random locations, front and rear, it was only 79.4 degrees.

I'm pissed!


That's just too good to not laugh at.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 08:24 AM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST