Speedometer is off. Any way to adjust?

[fe342185]

I have noticed over the last few weeks that my speedometer is off by a few miles per hour. When I am going 75 the needle shows 80. Also the digital trip miles is working in conjuction with the incorrect needle readout. I know this because the aftermarket GPS shows my speed and the tenth value is a little off. Also when I go through the radar speed readout through the toolbooth shows I'm going slower than what my needle shows.

With this issues it will make it seem like I have more mileage than the X has really traveled.

Thanks all.

[Dking05]

IF the speedometer is anything like the E39.. the higher mph you go, the more you will be off.(this was also proven via GPS) But 75/80 seems a tad too unlevel.
That or you have an other problem.

[motordavid]

Normal observation, imo...
all of us have the same situ, speedo-wise, though I recall many
comments on the odometer being accurate, as in "not exactly
connected" to the optimistic speedo reading.

From Search Tab:

http://www.xoutpost.com/bmw-sav-foru...edo-error.html

GL,mD

[X5Sport]

Not sure about BMW but VW/Audi/Seat/Skoda can have the accuracy improved by a correction factpor being applied by the dealer. I had a speedo replaced a few years back and the unit was over-reading by about 15% so the dealer 'corrected' it to within 2mph at 70mph. The change was made by changing a value in the ECU/Vehicle instruments computer or whatever system actually drives the speedo itself (not the wheel speed sensor which is just the input device).

In the UK speedos are allowed to over-read but never under-read with the limit being set at 10% +/-2mph @ 30mph on a calibrated test system.

My speedo indication is about +3mph @ 70mph when compared to a GPS system.

[blktoptrvl]

I read somewhere that the speedo cannot be accurate throughout the speed range. Meaning that if it is right at 100 mph it will most likely be wrong at 30 and vice-versa.

Also, you must consider the condition of the tires and how much tread has been worn off.

I used to check my speedo in all my cars against the mile markers on the highway and kept a conversaion factor in mind for each car.

Now, I just use the gps monitor to tell me the speed I am traveling - although I know is also off, but at least it is not dependent on the car/tires.

[fe342185]

It's not a big deal since I know it is not accurate and I know by how much. I just thought there as a way to wasily fix the issue.

BTW - My tires are new and OEM size so I it can only get worse when the tires wear.

Oh well. I guess the only time it will make a diff is on resale when I reach 100k. The 100k seems to scare peope and a 95k mile care seems to get better value than 100k. So if its off by 5% then then I will get to 100k mile 5k miles earlier. No biggie since I drive 7k miles a yr and I have 48k right now on my 03 X. At that point the X will be worth $3k resale anyway.

[m5james]

Originally Posted by blktoptrvl

I read somewhere that the speedo cannot be accurate throughout the speed range. Meaning that if it is right at 100 mph it will most likely be wrong at 30 and vice-versa.

I don't believe that in the slightest. If you use the OBC to read your speed, it is dead on and the needle is innacurate. The days of cable speedos are long gone, it's all feed by electronic sensors at the wheel. Unfortunately, BMW has been doing this for years, and there are varying opinions all over as to why they still do this. I don't know if there is a way to correct it, so in the meantime I break the law daily by going 5mph over, knowing in reality from the OBC and my GPS that I'm really only doing like 2-3 over.

[Cole]

Originally Posted by blktoptrvl

Now, I just use the gps monitor to tell me the speed I am traveling - although I know is also off, but at least it is not dependent on the car/tires.

Why do you say the GPS is inaccurate? At steady speed, on a level road, with good satellite coverage the GPS speed will be accurate to better than 0.5 mph.

[Cole]

Odometers tend to be more accurate than the speedo, I doubt you will have more than a 1% error in the odometer reading. Speedos over read slightly as most countries stipulate that the speedo may not under read at all, but may over read a little. Manufacturers therefore tend to err on the side of caution and make all their speedos over read slightly.

[TwinsPoppa]

Did you happen to change to non-stock size tires? I know, obvious, but just throwing it out there.