MPH? changing from 17" to 16"

[Mitch AC DC]

Planning on using my MG5{pfl}16" wheels with winter tyres this year. Then 'thought' does the smaller wheels affect the speedo mileage readings on Facelift model?. Did I hear correctly that this would increase range?

 

[EvTek23]

It may not depending on the aspect ratio of the tyre you are fitting.
You need to look at the current tyre size, and compare it the tyres and rims you are going to fit. It will be something like 215/50/R17, where the 50 represents the aspect ratio of the tyre. This is the important figure here as it defines how high the tyre wall is, and ultimately the rolling circumference of the tyre. If you are fitting a smaller rim size then the aspect ratio of the tyre will need to be larger to get the same rolling circumference. If it is, xxx/60/R16 then the rolling circumference is probably quite close. It's fairly easy on the internet to put in your tyre sizes and it will tell you the approximate rolling circumference.
If its a long way out then this will effect the speedo accuracy (it will read too high on the smaller tyre), the speed of the vehicle, and the recorded mileage.

 

[WigglePig]

Provided you are using tyres of the appropriate aspect ratio then there should be no change to the circumference/rolling size and therefore no change to the speedo reading.

 

[MickeySw]

did I hear right that this would increase range?

Yes, you would probably see a slight improvement in efficiency if you put summer tyres on 16” rims.

Winter tyres have a higher rolling resistance (being softer) therefore there will be no net gain using smaller wheels.