Quote:
Originally Posted by jmedia
Hello all, looking to increase the tire size on my sidekick just a little bit (a little over an inch) from stock as I have heard good reviews from performance and mpg but I have a question...
Which would effect mpg more? The sidewall height or the width of the tire? I (obviously) have to pick one or the other to increase to gain the extra inch I am looking for
Thanks for any input!
Josh
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First, changing tire size has a small affect on fuel economy, where careful selection of the tire itself can have a larger affect.
But if you strictly want to look at size:
Barry's Tire Tech
About half way down the page, I list a formula derived from the data - and the short version is that width is ever so slightly better than aspect ratio based on single increments. Please note that a single step up in size doesn't get you a whole inch in diameter.
- BUT -
You may have things that restrict what changes you can make in tire size:
1) Width of the rim.
2) Available aspect ratios
You only told us you have a Suzuki Sidekick, but didn't tell us the model year, and the type (2WD, 4WD) nor the tire size you are starting out with. I did a little research and it turns out that there were a variety of tire sizes mounted to Sidekicks - and while the rim widths are wide enough to go up a size or 2, many of the original sizes are maxed out on aspect ratio (75) and you won't find anything with a higher aspect ratio.
But you weren't considering going larger in rim diameter, were you? That would yield even more improvement over both a single increment in either width or aspect ratio - and then again a single increment is not an inch larger in diameter - and, again, the change is small compared to what differences there are in the tires themselves.