Taller tires should also correct this issue.
Taller tires should also correct this issue.
I just spoke to the Service Manager at the Nissan Dealership. He informed me that a few people have passed along this concern and that he is waiting to hear back from Nissan Canada. If enough people bring it to their attention, they will issue a bulletin with a solution.
He agreed that if they reprogram the ECU as they did 4 years ago for the Nissan Quest, the speed / RPM mix would remain as it is now. What I mean is, that once it is re-calibrated the Micra speedometre will display an accurate reading be at 4000 RPM when travelling 120kph.
However, if we leave the ECU alone and switch to the same tire size as the Versa 185/65/15, the speedometre will be accurate, the RPM at this speed will be about 200 lower and the fuel efficiency will accurately reflect the posted specs.
I will hold out to hear how Nissan resolves the issue but I would much rather see the solution resolved by increasing the tire diametre and leave my ECU alone. Good thing I held out before buying my winter tires!
We all need to notify our Service Managers of the issue immediately to see a resoltuion from Nissan.
Hop to it folks
Thanks for the info & update, MicraMan.
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View my fuel log 2015 Micra S manual: 5.0 L/100 km ... 56.5 mpg (Imp) ... 20.0 km/L ... 47.0 mpg (US) ...
Does anyone know why Nissan went with 185/60/15's instead of the more common 185/65/15's? Might there be an issue with clearance if the suspension bottoms out, possibly when turning into a corner? Or was it more for performance and handling reasons?
I decided to call Midway Nissan today. The service manager there advised me that, while I could go with a 185/65R15 tire without any problems, it would have very little impact on what the speedometer is reading, so I made an appointment for them to check it out. Then I stumbled upon this web site, and discovered that this difference in tire size at around 120 km/h represents around 4 km/h. http://www.tyresizecalculator.com/ty...ror-calculator
My problem with getting a different sized tire is that the speed change is progressive where as the Micra's speedo is constantly higher(poster earlier in this thread by "MetroMPG") Also, everybody is saying that the distance the ecu is calculating is correct, so wouldn't changing tire size affect this. (Honestly I like that it reads 4kph over, it will save me tickets in the long run) But i will speak to my service manager about it.
I would think that the ECU calculates the speed and distance traveled, using info from a single data point... somewhere aft of the transmission output shaft. Some guys are saying that they can be calibrated separately, but I'm not sure of that.
Radar evidence puts me at 54kph when the speedo reads 60kph. Trucks limited to 105kph blow by me like I'm going backwards when my speedo reads 100kph. My commute to work increased about 4km (i'm about an 80km commute) even though a considerable short cut opened up right at the same time I switched to the Micra. ( I have not measured the short cut, but it would be over 1km and probably closer to 2km). All my numbers are approximate, except for the radar.
A taller tire will go towards fixing the speedo and the odo (as it has on my car), and hopefully the dealer can re calibrate to make up the difference and for those wanting to keep stock tire size.
Ten Grand Tin Can
View my fuel log 2015 Micra S manual: 5.3 L/100 km ... 53.2 mpg (Imp) ... 18.8 km/L ... 44.3 mpg (US) ...
According to the tire size calculator we would need to put 205/65r/15 to put the speedo/odometer in the ballpark. That being said the question is will the micra take a 205/65r/15? Its a really big tire for the micra but I'm confident the motor and gearing could turn them no problem but would they physically fit without rubbing anything. According to the calculator the difference is also progressive so it would increase as speed increases (Maybe the tire grows as tire rpm increases) as does the micra speedo/odometer error.
Last edited by Pete; 11-01-2014 at 03:18 PM.
That seems like a big jump. This size brings the tire to 25.5 inch diametre. The spec tire size is 23.75 inches. Every .75 inch gain works out to a difference of approx 5 kph at 100kph. According to these calculations that would cause about a 10kph difference at 100kph. I was thinking of going to a 24.5 inch diametre which would give me about 5kph more. This is a 185/65/15 and the same tire as the Versa.
I will wait to see what Nissan says once enough of us notify our dealerships
So I took it in to the dealership to have the speed calibration tested. I advised them that the speed shows faster than the car is really going, and that this seems to be a common problem as other Micra owners have reported similar findings. What they did was drive it alongside another Micra, and found that both Micra's showed the exact same speed and deemed that nothing was wrong. I advised them to compare their Micra's to other cars on the lot.
At least I got a free car wash for my troubles.