Hey Team,
Just drove home with my new MINI. (08 MC Cab - top down, of course) I noticed that I was being passed like yesterday's egg salad sandwich. I fired up the GPS unit and found that I was tracking about 7 MPH slow (80 on both the "analog" and digital speedos, 73 on the GPS and roadside radar display).

Is there a owner calibration procedure or is a dealer fix only?

Thanks,

Al

 

My speedo runs about 2-3mph lower than my real speed. BMWs typically are like this. It probably also has to do with all the variations of wheels available on the MINI. There is no (approved) way for you to adjust it yourself - that'd be kind of dangerous, people could adjust it so that the car records less miles on the engine than it's really done.

 

GPS is traditionally lousy at measuring velocity...I wouldn't trust it.

 

Actually, GPS is *excellent* at measuring speed - with a typical number of satellites locked, if you're not getting within ~1.0 MPH accuracy, there's something wrong with your GPS. If you have WAAS available and enabled, the accuracy is *much* tighter - usually with 0.2 MPH.

Some people think that because the *positional* accuracy of their GPS can typically be off by 10-20 feet, and because the GPS updates speed about once a second, that this causes speed errors, but the GPS doesn't use your change in position to calculate your speed, so positional error has nothing to do with the error in speed measurements.

 

I have the same issue as Big Al, but to a lesser extent. My GPS typically agrees with the roadside radar units that the speedo is off by 2 or 3 mph. This leads to the questions - ho accurate are the roadside radar units and the GPS units? I've read arguments for both sides of the discussion. There was a previous post (I think it was in general Mini) about this issue, and I think I remember that someone posted a memo from BMW about acceptable tolerances, and they seemed pretty loose to me.

Does anyone know if the dealer can adjust the speedometer?

 

The dealer has indicated that this is not adjustable. Can anyone point to the BMW memo - I looked in General MINIs and have been unable to find the referenced memo.

Thanks

 

Sorry Big Al - the thread has been discussed under stock problems folder. I just did a search listing the word "speedometer" on that forum and found a few threads related to the speedo issue. Good luck, and happy motoring!

 

As noted, many have found the speedo to read 2-3 miles higher than GPS -- if you're getting a difference of 7, that seems too high on a brand new car and I'd ask your dealer to look into it further.

 

The spec is a percentage difference, but even 7mph difference at 80mph is nearing the limit (I hear tell it's allowed to read up to 10% fast.)

 

I also disagree with the person who said that GPS's are bad for measuring speed. Mine is spot on ... and my MINI is always 3-4 mph high from about 30 mph on up.

 

I have a BMW motorcycle and it is off by about 10%. There is a diode you can change on the speedo that makes it dead on. An interesting note is the BMW Police motorcycles are dead on.

 

When I picked up my car everyone was also passing me out. My wife was in back of me for the whole trip and confirmed that it was going 5mph slower than i thought i was going. On my next trip out i used the GPS and that also confirmed that the car was going 5mph slower than the speedo was telling me. Well, i guess slower is better than faster. LESS TICKETS.

 

It is legally mandated in the EU that the speedo must never read low, so all the manufacturers calibrate them to read 5% high or so. Here, the threat of lawsuits causes auto manufacturers to do the same thing.

Most of the difference in the range of 2-9% high reading reported on NAM is from wheel/tire size variation. That's one of two ways to affect the error.

Mine reads 5% high, confirmed with both GPS and speedo-calibration mile-markers on I-5.

The other way to correct the speedo error with great precision is a gadget called the Electronic Ratio Adapter, (yes, the ERA) which sits between the wheel-speed sensor and the computer, and which adjusts the digital pulses that the speedo sees, by a set percentage. Around $200. (I've used one, but not on a MINI. Worked great.)