Hi,
I know the size of the the tyre knocks out the speedo thats fine but apparently it effects the fuel economy. But is that true in my case?
I have to drive 70k to work and back every day and hit 3 sets of traffic lights so dont hardly stop.

Is the bigger tyre size better on the freeway doing 100kmh?


thanks for any input, ill be getting new tyres in the next day of so.

 

i'd assume a drop of betweem 10-20% in fuel economy.
the larger tires will cause the engine to run at a lower rpm at any particular speed, but they are also heavier than the smaller ones, will raise the vehicle slightly and increase wind resistance.

do some searching in the forums here and you can get some better information about it, as well as recommendations for regearing to compensate.