| Most people see the best mileage with stock size tires. 265's shouldn't have much of an effect, but they most likley will hurt rather than help your mileage. If you were to step up to 285's you would lose mileage for sure.
If your looking for better mileage, honestly get an entry level programmer. Almost all of them guarentee an improvement in mileage. That combined with a larger freer flowing exhaust (which will lower your exhaust temps if you tow) will get you the mileage improvements you want. Most likley at least 2 mpg. And as long as you don't add over 90 horsepower, your still completley safe, and will not risk ruining any part of your truck. |