Tires: fuel . smaller tires have better fuel mpg, fuel economy, careful selection

Question
would original equipment tires have a better higher mpg.. then having bigger  second manufacture option tires....  14" tires give u higher mpg/  then 15" tires  yaris origianl is 14" i want higher gas milage ... should i go back to the 14" i have 15" on now

Answer
John,

Long answer:

http://www.barrystiretech.com/rrandfe2.html

Short answer:

This a complex situation and tire size plays a small role in fuel economy.  However, there is a HUGE range for tires within a given tire size.

Generally speaking 15" tire will give you better fuel economy, but careful selection of a tire has a bigger pay off.