After taking delivery of a new E92 325i coupe a week ago, I am a bit disappointed with the fact that the speedometer indicates 100 kph while the car is actually only doing 95 kph (extensive test on flat motorway using tom tom 910 GPS).
Is this sort of error considered normal or acceptable?
Can anything be done about it?
The car is absolutely brilliant in all other respects.
"Bob Morrison" wrote
Typical.
No, not really. You *can* get the actual speed from the computer if you fiddle around. The reason it's fast is a combination of EU and US requirements - it must never read low, essentially.
FloydR
Nothing to stop it being accurate - or the over-reading error being tiny.
There are advantages to a maker to deliberately have the device over-read by such a large margin. Makes the car appear faster than it is. If it extends to the odometer a milage based warranty runs out sooner and MPG appears better too.
"Dave Plowman (News)" wrote
It doesn't.
Pete
You used to be able to update the software/firmware speedo calibration factor but I don't know if that's still possible.
Perfectly normal. You should be able to get a more accurate reading by doing a reset of the OBC if necessary.
Years ago, Road & Track magazine routinely included speedometer error (at 30 and 60mph, IIRC) in their road test info, and Motorcycle Consumer News still measures it @60 mph for tested motorcycles. Worst error I personally recall was my 1976 R75/6 cycle which read 125 at its top speed of 102.
Tom K.
"Bob Morrison" wrote
Short of getting slightly larger tires, not really.
Generally, speedos are allowed to read up to 10% high.
Pete
It is both normal and acceptable.
My car is a '94 E36 that came with 225/55x15s. I've changed the tire package on my car to a 225/45x17, and when my speedo reads 80 on a measured mile, the stop watch is off by just fractions of a second -- meaning my actual speed is about 79. The 17s on my car are just a tad larger than the 15s that came on it, which has the effect of slowing the speedo. As a matter of design, the speedo reads faster than actual speed so that when you set your speed in compliance with the roadside singage, you do not run afoul of the law.
If your car is really doing 95kph at an indicated 100kph, then your actual speed and indicated speed is pretty much the same as mine, and I had to change my tire package to get where I am.
Ford's do this BMW's don;t, or only by very few % (comensurate with tyre wear etc.)
"R. Mark Clayton" wrote
Honda also did this and got slapped with a class action lawsuit because the warranty was actually shorter than it may have appeared.
Pete
I'm not quite sure what you mean. Every BMW I've owned has had a speedo which over-reads by about 5 mph at 70. I've owned other cars which are accurate - or at least to a needle's width.
Incidentally tyre wear is a red herring too - if the car is accurate with new tyres the speedo will over-read as they wear.
A pulse counting instrument should be accurate to +/- 1% across the entire range. So allowing for it never to over-read should read no higher than
102 at a true 100.Run along.
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