So my civic is not bad on gas to start with, but I have a set of 17" Motegi Wheels, with the car dropped to perfection, suspension by tokico. The wheels are slightly heavy, and I got told a set of 15" lightweight rota wheels would help me take of the line a little quicker, if I do buy the rotas, shud I expect more fuel efficiency as well? Kinda like a win-win situation?

 

You'll get better fuel economy, better performance, and overall better ride quality dropping down to a smaller wheel size than those overly large 17's. Also, if you're REALLY looking to fuel economy, get a narrower tire to cut through the air.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by toyomatt84 &raquo;</TD></TR><TR><TD CLASS="quote">You'll get better fuel economy, better performance, and overall better ride quality dropping down to a smaller wheel size than those overly large 17's. Also, if you're REALLY looking to fuel economy, get a narrower tire to cut through the air.</TD></TR></TABLE>

All true.

The reason for the first statement is because of the added weight of the wheels AND tires with larger diameter wheels. If you choose a tire whose outer diameter is the same as your stock tire size - which you should - then there won't be any difference due to effective gearing (a smaller diameter tire will give slightly worse fuel economy).

However, the differences in fuel economy due to these factors are not likely to be all that great (like under 1 mpg difference). The factors that make big differences in fuel economy, aside from the car you drive (obviously), are your driving style (how hard do you accelerate), keeping the proper inflation in your tires, etc., as noted here.

 

Yea, all definitely precise statements, and yea, I try to accelerate as slow as possible as much as I can, believe it or not, old people in minivans pass me and stare like wtf!? LoL, all my friends make fun of me but with gas prices nowadays, I should be making fun of them in their shitty gas guzzling V-8 camaros, and trans ams!

 

I have read somewhere that efficiency will be affected by different makes and models of tires. I do believe there was one government looking into getting some form of testing and rating for this to be stamped on the tire, much like the UTQG but useful.