I've noticed that the reported speed on our 2015 Countryman All4 is higher than the tracked speed on my GPS and also when I encounter Radar Speed Signs.

While the error is perhaps 5%, no other car that I have owned in the last 10 years has been this inaccurate.

My 2002 Volvo S60 is dead nuts accurate for example.

The dealer says that the error is due to the fact that our car has 17" wheels not the optional 18" wheels and that the manufacturer is required by law to set the speed to the size of the largest wheel.

Really? I'm a freaking engineer and they're feeding me that line of BS?

Has anyone else encountered this and if so, were you able to get a resolution.

As far as I'm concerned our warranty will expire sooner than it should and my mileage, which isn't stellar, is worse than reported.

 

the EU has a law that imposes massive fines to any auto manufacturer whose cars display a speed that is slower than the car is actually going

the fine is imposed per car

as a result all new euro manufactured cars report a higher speed than actual speed

 

watching mile markers on the interstate, the odometer appears to be accurate

 

With all of the complaining you are doing about this car, perhaps you could have done some research/reading up on it before you bought it? And, if you are a 'freaking engineer', i'm sure you can (eventually) figure out how to adjust your seat and drivers side mirror so that you can see out of it.

 

rather than offer some constructive comments.

This car was a gift for my wife. I much prefer my 13 year old Volvo, but if I have to pay for it and I have to drive it, I would like to correct these minor issues.

If you have nothing positive to contribute to the thread please don't reply.

I understand this now...
bmwr606 has not made any friends yet
mikey_t has not made any friends yet

 

I adjust in my head. I think it's 2 MPH off at any speed (not a percentage of speed). Can someone confirm?

Also, it's possible to remove the adjustment on the digital speed display (but not the analog dial) by picking up a BMW D-CAN cable, and reprogramming this yourself. That's what I plan to do soon, I'm more interested in things like enabling one-touch control of the sunroof, unlocking the car when pulling out the key, and many other items.

 

Reprogramming thread: https://www.northamericanmotoring.co...r60-guide.html

 

This is exactly what I hoped to find. The methods to appropriately program the system.

Kudos to you DWooderson!

 

My CM is 2 mph difference, not a percentage. It happens at all speeds confirmed with multiple speed display devices all over the friggin road. The town next to me makes a hefty chunk of change dinging speeders with all kinds of traps & radar, they love those toy guns. It took me 5 minutes to get used to the idea of having to mentally adjust.

I'd reprogram if I knew someone with the tools, not worth the headache of going at it myself. Gotta fix the leaking dishwasher first.

 

mine was 1.9 mph off ... upping the tires size from 225/45R18 to 225/50R18 brought both the digital and analog speed displays spot on

 

As the tread on a tire wears down it will increase the number of revolutions per mile to the extent that a typical speedometer will overstate by around two additional percent (that's more than 1 mph when doing 60 mph). No speedometer affected by tire diameter can be constantly accurate nor can it have a constant delta to something it can't measure accurately in the first place.

Using larger diameter tires does in fact reduce the size of the intentional error in MINI speedometers. It also affects the odometer which does not have the intentional error.

The MINI computer has consistently overstated my mpg by an average of two mpg over 31k miles in two MINIs. The speedometer is off by a percentage. The error in mph vs. GPS increases with the speed driven. About 5% is in the ballpark.

 

my speedo was off 1.9 mph from 20 mph to 120 mph ... a constant 1.9 mph not a percent

checked with an aviation gps with 0.1 mph precision and double checked with a stop watch

all speed measurements made with a codriver doing the measurements and using cruise control

 

But you then claim to have corrected the error by installing tires that were 3.5% taller. That works for 55.1 mph where 57 would have been falsely indicated before. At a true 120 mph the new tires would cause the speedometer to read 118 instead of the previous 121.9.

How do you explain correcting a constant error with a percentage change in gearing?

 

it's a constant change not a variable change

 

Ignoring tire wear, it's a constant 3.5% percentage change in gearing. The effect still varies with speed travelled. 3.5% of 121.9mph is a lot more than 3.5% of 57mph.

At what speeds did you repeat the test with the 225/50 tires?

 

i did not set out to correct the speedo by changing tire size

since my all4 was delivered with summer tires, pirelli p7 225/45R18 (25.9 inch od), i knew i would need winter tires

i bought a set of 16x6.5 et 46 mini euro alloy wheels from ecstuning.com and then went to my local independant tire store to see how tall of a sidewall tire would fit ... taller sidewalls giving better pothole protection

205/70R16s fit with no rubbing, even with the car loaded until it was sitting on the rubber snubbers ... anything bigger rubbed, either when sitting on the snubbers (taller size) or at full lock (wider size)

so i ordered a set of dunlop grandtrek sj6 studless ice and snow AT truck winter tires 205/70R16, they are 27.3 inch od

after fitting them i knew they would change the speedo reading and found that the speedo went from 1.9 mph over actual (with the oem pirellis) to 0.9 mph under actual

at about the same time, the oem tires got very loud ... 4000 miles and 50% worn

i knew i wanted michelin pilot super sports, so back to the tire store to see what sizes fit ... 235/50R18s are the same od as the dunlop winters but they rubbed the front strut on the inside when loaded to the snubbers

backed down to 225/50R18s (26.9 inch od) and they fit with no rubbing ...

ordered a set of the pss and after fitting found the speedo to be spot on actual speed ... a serendipity if you will

 

there is an unknown with the speedometer ... how is the ecu changing the speed it measures to the speed it displays ... it is not a mechanical system with a bowden cable like in the old days, it is a digatal system ... mini can manipulate the displayed speed any way they choose

given that my odometer was less than 0.1 miles off in 10 miles (0.0001% ) i think the ecu know exactly how fast the car is going and they are adding a fixed amount (1.9 mph on my car) to the displayed speed

 

I agree that BMW may be adding a fixed amount or a percentage as others have also reported, and that all years and models of MINIs may not be the same. I just don't see how changing tire diameter can equally change the amount of error at all speeds if it is a fixed amount adder.

If the OEM tires were worn when you measured the 1.9 overstatement then I would expect the snow tires to be understated by 0.9 and the PSS to be spot on around 66 mph only. If the 1.9 overstatement was measured when the OEM tires were new, then the speed producing 0.9 and 0.0 error would be around 50mph only.

This is why I asked at what speeds you checked after changing tires.

 

i did the initial check with less than 1000 miles on the original tires, as i have done with every new motor vehicle i have owned

the idea that the speedo is not linear harkens back to cable driven speedo days when a cable spun a disc with a magnet attached that pulled the needle of the speedo ... this type of gauge was notorious for an error that varied with speed

that is no longer the case ... speedos are now very consistent in the error displayed ... this goes back to my first digital driven speedo in 1987

 

"the idea that the speedo is not linear harkens back to cable driven speedo days when a cable spun a disc with a magnet attached that pulled the needle of the speedo ... this type of gauge was notorious for an error that varied with speed"

That type of error varied toward both ends of the gauge's range.

The car has to be counting revolutions in order for a change in tire size to affect it. Changing the diameter changes the revolutions per mile.

It the car knew true speed it would be showing true speed plus adder no matter what tires you were running the same as a GPS speed calculation is unaffected by tire size.

 

exactly what i have observed ... tire diameter changes the accuracy of the displayed speed, but the error is constant across all speeds i have measured, 20 mph to 120 mph

why don't you try your own observations instead of spouting nonsense

 

I have my own measurements vs GPS. I have multiple sets of tires with different diameters.

Instead of accusing me of spouting nonsense why don't you post your data with the PSS tires?

 

This topic keeps coming up and I find it odd that people don't notice that other cars have accuracy issues as well and it is all by design.

From Car and Driver in 2002: http://www.caranddriver.com/features...ometer-scandal

Direct quote:
Yes, ladies and germs, we are scooping 20/20 and 60 Minutes with this scandal: Speedometers Lie! Okay, "exaggerate" may state it more aptly, if less provocatively.

When traveling at a true 70 mph, as indicated by our highly precise Datron optical fifth-wheel equipment, the average speedometer (based on more than 200 road-tested vehicles) reads 71.37 mph.

Sorted by price, luxury cars are the least accurate, and cars costing less than $20,000 are the most accurate. By category, sports cars indicate higher speeds than sedans or trucks. Cars built in Europe exaggerate more than Japanese cars, which in turn fib more than North American ones. And by manufacturer, GM's domestic products are the most accurate, and BMW's are the least accurate by far.

today, nearly all speedometers are controlled electronically. Typically, they are driven by either the vehicle's wheel-speed sensors or, more commonly, by a "variable reluctance magnetic sensor" reading the speed of the passing teeth on a gear in the transmission. The sine-wave signal generated is converted to speed by a computer, and a stepper motor moves the needle with digital accuracy.

In the U.S., manufacturers voluntarily follow the standard set by the Society of Automotive Engineers, J1226, which is pretty lax. To begin with, manufacturers are afforded the latitude to aim for within plus-or-minus two percent of absolute accuracy or to introduce bias to read high on a sliding scale of from minus-one to plus-three percent at low speeds to zero to plus-four percent above 55 mph. And those percentages are not of actual speed but rather a percentage of the total speed range indicated on the dial. So the four-percent allowable range on an 85-mph speedometer is 3.4 mph, and the acceptable range on a 150-mph speedometer is 6.0 mph.

The European regulation, ECE-R 39, is more concise, stating essentially that the speed indicated must never be lower than the true speed or higher by more than one-tenth of true speed plus four kilometers per hour (79.5 mph at a true 70). Never low. Not even if somebody swaps a big set of 285/35R-18s for stock 255/45R-16s.

Hope this helps.

 

A state trooper actually told me how to check my speedometer, simply set your cruise control on the interstate to any speed and time yourself between from one green mile market post to the next. A quick calculation and you know your speed. He mentioned that the majority of vehicles speedo show they are going faster than they actual are to avoid car manufacturers from getting sued.


Here is a chart that converts seconds IT TAKES TO TRAVEL ONE MILE to miles per hour,"

Speed is distance divided by time. If the distance is 1 mile and the time is T seconds, then the time in hours is T/3600, and the speed is

Speed = (1 mile)/(T/3600 hours) = 3600/T
Or just look at the following table:

Obviously, if you travel the 1 mile mark in 60 seconds, you will be driving 60mph.

Seconds MPH
------------
36 100.0
37 97.3
38 94.7
39 92.3
40 90.0
41 87.8
42 85.7
43 83.7
44 81.8
45 80.0
46 78.3
47 76.6
48 75.0
49 73.5
50 72.0
51 70.6
52 69.2
53 67.9
54 66.7
55 65.5
56 64.3
57 63.2
58 62.1
59 61.0
60 60.0
61 59.0
62 58.1
63 57.1
64 56.3
65 55.4
66 54.5
67 53.7
68 52.9
69 52.2
70 51.4
71 50.7
72 50.0
73 49.3
74 48.6
75 48.0
76 47.4
77 46.8
78 46.2
79 45.6
80 45.0
81 44.4
82 43.9
83 43.4
84 42.9
85 42.4
86 41.9
87 41.4
88 40.9
89 40.4
90 40.0
91 39.6
92 39.1
93 38.7
94 38.3
95 37.9
96 37.5
97 37.1
98 36.7
99 36.4
100 36.0
101 35.6
102 35.3
103 35.0
104 34.6
105 34.3
106 34.0
107 33.6
108 33.3
109 33.0
110 32.7
111 32.4
112 32.1
113 31.9
114 31.6
115 31.3
116 31.0
117 30.8
118 30.5
119 30.3
120 30.0
121 29.8
122 29.5
123 29.3
124 29.0
125 28.8
126 28.6
127 28.3
128 28.1
129 27.9
130 27.7
131 27.5
132 27.3
133 27.1
134 26.9
135 26.7
136 26.5
137 26.3
138 26.1
139 25.9
140 25.7
141 25.5
142 25.4
143 25.2
144 25.0

 

I agree this keeps coming up. maybe it's time for a sticky if anyone has the access?