Both my Garmin nav and the TORQUE app on my tablet say im doing 65ish when i have cruise set at 68 on flat roads. This is GPS miles. This annoys me for a few reasons, my MPG is off, I have no idea how far I have traveled, as the maps and odo dont agree...

Is there any way to calibrate this?

 

I think what you are observing is normal. Optimistic speedo especially. I have a slightly larger speedo error than the one that you are citing. Have checked the ODO against the GPS and also against a measured stretch of highway and found the ODO to be accurate to better than 1%. Similarly the computed fuel milage is quite accurate. I have tires that are specified to be OEM diameter.

The optimistic speedo error and accurate ODO may be intentional and may be the manufacturer's response to litigation that cost them some $'s.

I do not know of a recalibraton procedure other than just being mindful if the speedo error.

 

I noticed my garmin displays I am going 2 mph slower than the speedometer says. I tried a friends garmin with same results.

 

Mine is off by 2 mph also. I adjust my speed keeping that in mind.

 

Everybody's is. This issue has been hashed out ad nauseum.

 

I like the fact that mine is about 2-3 MPH faster than what i'm actually doing. Helps appease my need for speed without having to worry about the CHP

There is a way to fix this in NCS Expert if it really bothers you. Search for the forums and see if there is someone local to you who can code it out for you if you don't want to invest the money and time to learn NCS.

 

my cms all4 speed is 1.9 mph faster than gps with the stock tires, 225/45R18, 25.9"OD

with my winter tires the speedo is .6 mph slower than gps, 205/70R16, 27.3"OD

my summer tires will need replacing soon after the winters come off and i will be installing 225/50R18 tires, 26.9"OD and that should make the speedo close to the gps

scott

 

Here's a handy little calculator to factor in differences in tire size.

http://www.miata.net/garage/tirecalc.html

 

Only 2 mph off...pretty accurate for ANY SPEEDO, ESPECIALLY A MINI....
Remember, as tires wear, it will get worse, then be almost correct when you put new tires on...it is calibrated to ALWAYS say the car is ABOUT 1+ mph off, mostly due to a few laws.

 

I'm off 4-5 mph at highway speed. It reads 70 when I'm doing 65-66. This is backed up by 2 GPS units. I had my coworker use a LIDAR to track my speed. At 70 indicated it was at 66 in the LIDAR. (LIDAR is laser).

 

My 2009 Clubman is off by 9km/hr, consider yourself lucky!

There is no way to recalibrate it, no. I've already asked the dealership.

 

You can fix it in the OBC's secret menu. I did. Search for it.
EDIT: Sorry I was thinking about something else - the MPG - which I had fixed via the OBC. You can "fix" the speedometer issue by gettting taller tires.

 

Yeah... i set my cruise at 68.. i get the best mpg there, and im still passing people... even though my real speed is 65....

 

I believe European laws require them to err the calibration on the high side, so they actually boost it in the computer. Our old Freelander exhibited the exact same behavior as the Mini. Accessing your car's computer using NCSExpert will give you the option to toggle this off.

 

My NCS coder made the adjustment when doing a bunch of other neat changes for me.

 

as other's have stated, this is normal for every car. 2mph really isn't a big deal.

 

The easiest way is get larger diameter tires.

 

This. It's a "problem" that the computer does on purpose. It can be turned off if you know how to use NCS Expert or find someone, like myself, who can do it for you.


I also personally like it. It's a little extra cushion for the police/speed cameras. I've found that when my car says I'm doing 40 I'm actually doing 35. car says 70 and I'm doing more like 64. I know the speedo says I'm going faster than I am but it still keeps my brain happy seeing the higher number and keeps my wallet happy by not getting tickets!

 

Mine was 4mph off at 69mph (actually doing 65 according to my GPS) I switched from 205/45-17 tires to 215/45-17 tires (about 10mm taller) and now my speedometer reads 67mph and GPS indicates 65mph.

 

Just to throw this in.......Does not a erred speedo that says you are going 4 mph over the actual speed ALSO give you erroneous tally of the total miles ( Say for Warranty and such ), AND the wrong MPG? So the Odometer will say I have more miles on my Vehicle that I really do and that I am getting better gas mileage than I actually am?

 

In 'vintage' cars where the speedo/odo were driven by a cable - corrections to the cable gearing would affect both the indicated speed and the indicated elapsed miles. I suppose that one could in theory go into the clockworks of the odo and do a separate correction on just the odo.

I am assuming that on modern electronic systems that the relative errors on both the speedo and the odo could be separately calibrated.

I have found on my MINI that the speedo is optimistic in a similar amount to the errors stated in this thread and the odo is rather more accurate. I have checked both against the gps and against a measured distance on freeways against the milepost. Also the indicated mpg is accurate.

 

car companies set speedos to be a little bit faster for insurance purposes. basically you can never accuse their speedos of being the reason why you were speeding. they give themselves a little bit of "slack".

 

I'm not sure I'm ready to buy into the full conspiracy theory, but yes in theory if you show 70mph and you're only doing 66, then yes your mileage will be 6% off, for the better, and your warranty will expire 6% sooner. So when your odometer shows 40,000 miles, you've traveled more like 37,714.28 miles. That of course assumes your tire circumference remained constant that entire time, which it won't, but suffice to say make sure you make an appointment when you hit the high 30's. For sure if you change tire size, then you can be sure you're making an adjustment to your odometer vs. actual readings.


I also find it interesting that an OBD Gauge plugged into the OBD port shows different numbers than the readout- I would have thought those would have both pulled from the same computer, but it's interesting to see it's in fact different, and both are higher than what the GPS says. My hunch is the Ultra Gauge is closer to "actual" the speedo readout has been enhanced for my protection, and the GPS is reading a little slow.

Cruise set at 70, Ultra Guage shows 67.7, and GPS shows 66. go figure.

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No, although the speedo is often about 4 mph faster at 60 mph, the odometer
tends to be very close to spot-on in MINIs. If you used a taller tire to correct
the speedo error, you'd actually end up with an odometer that reads 5-8%
less miles per mile driven.

 

i can confirm this

with the stock tire size, 225/45R18 (25.9" od), my speedo was 1.9 mph higher than gps speed but the odometer was spot on

for winter, i installed the largest tire i could, 205/70R16 (27.3" od) and my speedo is now .6 mph lower than gps and the odometer reads a little low, about .1 mile in 5 miles traveled (2%)

scott