I have a 5 km/h difference between the speed I set on cruise control vs the real speed shown on the speedometer can any body help me ?

 

the car is nissan maxima SR 2016

 

Yes, I can help.

Only pay attention to the speedometer.

 

im wondering is it just my car or its a common issue?

 

3 mph diff. in my world. Would bug me too but I'd live with it. Besides, 5 kph diff. is not valid to real-world speed enforcement. Bet you find that this problem is not common to our Gen 8's.

 

I wonder if tire size could factor into your speed difference. I'm not sure but I've read that some systems read speed from transmission gearing and some systems read speed from wheel sensors. Wonder if non-OEM wheels/tires could throw off the diff. between speedometer and cruise control speed settings?

 

This speed difference you mention. Does this occur with no car in front of you?
If your car has ICC (Intelligent Cruise control) you may not reach the desired speed due to a car traveling in front of you.
How do you tell ? Look at the display while you have the ICC set if there is a car being detected you will see this as full green color
car and not a outline. Also what distance setting are you using for car in front of you one ,two or three bars?
Good Test would be go on completely open road set your speed and have three distance bars displayed.
FYI I have never had this problem with my 2016 Max Plat

 

actually yeah this is happening with no car in front its weird to be honest never saw something like this

Lets say im driving 100kph and i wanna set the cruise control the cruise control will automatically be set on 95kph.

 

my tires size is 245/40 R 19 94W do you think i need to change my tires?

 

According to Tire Rack, that is the stock size, so I'd say no.

 

Is this a new problem or has it always been there?

 

from my experience, not all tires with the same "size" have the same overall diameter (including tire pressure, and thread thickness).
your delta speed will only be zero if you can find a set of tires with the diameter that the software is programmed with.
please let me know if i am out of my mind.