Alloy wheel change and tachometer reading

[ds3nisias]

Hello guys,
i have a ds3 with 17 inch rims and summer tyres of size 205/45 R17.
Currently, i want to buy a set of 16in rims with winter tyres. I've been told that the corresponding tyre size is: 195/55R16.

My question is: can i remove the 17in wheels and replace them with the 16in wheels and drive off or will i have any problems whatsoever like wrong km reading?

Thank you

[cyclone]

Type in google "tire size calculator" that will tell you what the difference will be between your stock size tires and any tire you are thinking of putting on.

[ds3nisias]

Excellent website. Thank you.
I am thinking to go to 16 rims because they are a bit cheaper than the 17.
As i see in the website i can choose so many different sizes that would fit in the 16in rim.
Any recommendations? Should i go for the same width or more? Fatter ones to be more comfy or not?
Anything would be helpful.
It seems like such a big variety though..

[BenS]

I wouldn't go wider than 7" (normal width), as they might catch on the wheel arches at the front on full lock and the increased rolling resistance will worsen fuel economy. Plus wider tyres are more expensive.

[pmatil]

195/55/16 is the equivalent 16" yes. I've had them with my winter tyres on both DS3s. If you go for some other size make sure the speedo does not show too little.

[Andres]

Something weird to take into account:

The speedometer measures aprox 4km/h* more than the real speed, but the car "knows" that difference (error). Measured by GPS, when the speedo measures 60km/h the GPS measures 56km/h.

The "fun fact" is that, when connected to a OBD scanner capable of reading speed (provided by the ECU) when the speedo measures 60km/h, the OBD measures 60km/h!! that's why I say that the car actually "knows" the real speed.


*I'm located in Latin America, metrical measurement system.

[Andres]

The "fun fact" is that, when connected to a OBD scanner capable of reading speed (provided by the ECU) when the speedo measures 60km/h, the OBD measures 60km/h!! that's why I say that the car actually "knows" the real speed.

EDIT: I wanted to say...: "the OBD measures 56km/h!!!" my mistake, sorry!

The fact is that te ECU actually knows that difference of 4km/hr. Or I may say it alters the speedo measure by 4 km/h. ¿Safety reasons? (speed traps?)