Hi, I'm pretty new to this forum, and just recent purchased a R56, i noticed that the speedometer is off. I brought my baby back to the dealership and they told me that it's standard for the Mini. Just wondering if there are anyway that i can fix her so it can show me the actual speed?

 

You didn't say how much it's off. I have a 07 MCS and mine is 2 mph fast. I think that you will find that most car speedo's are calibrated a little fast. Of course if you change your tire diameter it will affect the accuracy also.

 

well...it depends on how fast i drive, on local 35-50, it will be off around 3-5 miles. on freeway when i drive 80mph my actual speed was ...71 mph.
i checked it in w/ the dealer they told me something like: it will be off around 10% of the actually speed.
Beside i got the 16" stock wheels... so i don't know if it will make any different?

 

Wow yours is off more than most. My R56 was off about 4% from the factory. The dealer is right that the manufacturer is allowed to be +10% error. A really crude solution would be to open up the speedo and reposition the needle, but then your speedo would read high some places and low in others, depending on how much you moved it. Not really recommended unless you're pretty much a technician with steady hands!

 

i hated it... what's the point of having a speedometer for when it's not telling you your actual speed? :(

 

I'm guessing they do it because they know everyone speeds about 5mph over the limit at least and the government probably had them do this so the truth would be that we are all closer to the speed limit than we believe. Kinda a placebo we think we are going faster, but really we are driving legal speeds ( that is if you only do 5 over )

It can also be a great way to make cars seem better than they really are...it feels good when you are driving 80 and it only feels like 70, but it kinda sucks when it actually is 70 but you don't know that haha

 

Funny, I just figured this out, thought it was because I put new wheels on, at least it explains why I didn't get pulled over when I thought I would have.

 

lol... you still have some rooms on you pedal keep on pressing it

 

Yep, that's quite a difference. I have a Garmin GPS and it shows my speed and it is consistently 2 mph slower than the speedo is registering. No big deal but I don't buy that 10% off is acceptable. The tires are suppose to be sized for the proper diameter thus the correct speed. My tires are 205/45/17 which makes the height 24.3 inches. 235/40/17 would be 24.4 inches and 195/55/16 would be 24.4 inches. If your tire diameter/height is about 24.3/24.4 inches then it's not the tires.

 

Get a radar detector and you want have to worry about it.

 

Got one of those also

 

Actually, it's even worse than that. The allowable specs for the MINI speedometer are:

1) May not read too *low*, not even by 1 MPH.
2) May read high by up to 10% of the vehicle's actual speed, PLUS an additional 2 MPH.

So, if your true speed is 70 MPH, the speedometer can read anywhere from 70MPH to 79 MPH and still be "within spec".

 

That's kinda' crappy. I can understand that they don't want it to be under, but, in your example, to be as much as 9 mph fast is inexcusable. These things are not precision instruments, but surely its possible to have a speedo that is accurate within 2 mph.

 

I believe that there are laws in the USA that require speedometers to read equal to or greater than the actual speeds. So, auto manufacturers aim at some value over the actual speed so that with the normal variation in mfg. tolerances they don't end up with a speedo that reads too slow. The MINI is not alone with this situation. It is typical of all cars. Some may have tighter tolerances than others, but I can recall this issue with cars as far back as the 1960's.

 

Just curious, how did you determine that your speedometer is off? Comparison to a Garmin unit? Is it possible the Garmin is off, instead? Are the nav units always dead-on? Just asking, I don't own one, but the large error you're reporting seems very unusual.

 

Modern Nav units are extremely accurate when it comes to speed, because they do NOT use your calculated position to update your speed. Instead, they use the Doppler shift in the signal they receive from the satellite, in much the same way that a radar gun operates.

If you have a good-enough satellite lock that your GPS unit isn't complaining about "degraded performance", then your GPS speed error is going to be less than 0.8 ~ 1.0 MPH. If you have a good lock on 8-10 satellites, then the error is going to be more like 0.2 MPH.

 

So I guess it's got to be a bad speedo...

I know if mine was off by 10mph I'd certainly insist it be fixed by the dealer, it's certainly not normal operation. I agree that a couple of miles an hour may be expected, but 70mph vs. 60 mph is a very large error, over 15%.

 

If you can show your dealer that your speedometer is showing 70 MPH when you're actually going 60 MPH, they'll re-calibrate it, since the maximum allowable reading for a road speed of 60 MPH is 68 MPH on the speedo.

Or, you could just look up "speedometer calibration" in the Yellow Pages and have an independent shop adjust it for you. Make sure they know that you have a MINI, and that their calibration machine needs to be able to drive *all four* wheels, unlike many cars where only the front wheels need to be driven in order to adjust the speedometer.

 

yup ... that is exactly what they've told me.... i just wasted 3 Gals of gas for that info :(

 

Is there really such a thing as wasting gas when you're driving a MINI?

 

What you didn't take into consideration is that if there is a 10% discrepency, then when you have driven 10,000 miles will your odometer read 11.,000 miles? Does that also relate to a 10% depreciation when you go to sell your car???

 

The odometer may be a different system and have a different accuracy.

 

No. Because of the way the speedometer and odometer interpret the information from the wheel speed sensors, speedometer accuracy is *completely* unrelated to odometer accuracy, UNLESS the speedometer error is the result of non-stock tire diameter.

There have been many posters here on NAM (myself included) that have measured their speedometer error to be in the 4-5% range, while odometer error was less than half a percent.

 

Have you tired setting the tach to show the speed in the digital readout? IIRC, I get a slightly different reading than the analog speedo.

 

I had stock 17" tires on my MCS when I got it. I added 15" snow tires for this winetr, and I just put my Stock 17" tires back on the other day and the accuracy of my speedo has improved quite a bit. It was way off with the 15" tires now its off 2-3 mph with the stock tires. Not that bad. (testing using my Garmin Nuvi GPS)