Much like a fat guy in a speedo, there are just some things that jump out at you and are impossible miss. Unfortunately, many of the things that go awry with our Jeeps are not so obvious. Our past story (“Gaining Through Losing,” Oct. ’11) got us thinking about it. Not the fat guy in the speedo, but the impact that tire selection has on mileage. In that story we picked up 0.63 mpg by simply losing 28 lbs of rotating weight at each corner, or 112 lbs of total rotating weight lost. But what about the tread design? Despite using two different brands of tires, we kept the tread design as similar as possible for that test. As we kicked the idea around more and more, we decided we likely had enough data from enough different vehicles to figure out just how different tires affect mileage.
Now we aren’t saying all the changes we’ve recorded below are from tire weight. Maybe they are from the aggressiveness of the tread, but how much? We all know that going to a bigger tire with the same gears kills mileage, but how much? Or does it? The fact of the matter was we just weren’t sure anymore. But, fortunately, we keep tons of records, including when we swapped tires and how many miles were driven on a given tank for just about every vehicle we own. So, we broke out the calculators and notebooks and set about figuring just how a particular set of tires changed our mileage.?>
The Guinea Pigs
Our cast of characters is long and convoluted. We even included Editor Hazel’s tow rigs over thousands of miles.