Compression Ignition Addict
Join Date: Oct 2011
Location: Jenks, OK
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Gears, tire size and mpg
Just got this truck. It has 37" nittos on it with an 8" ProComp lift. I have a hunch it has the stock 3.73 gears in it.
I am thinking about swapping to 4.30 or 4.56. I'm also wanting better mpg because mine BLOWS (8-9) right now (little womans 06 is getting 14.4 stock with 6" lift, 35" tires and straight 3" pipe). I just ordered an X3 with Innovative tunes. My old thoughts were that if I went with lower gear that my performance would improve, but mpg would get worse, but in the case of these big trucks, lifted, big tires, I think it would actually improve my mpg? Right now at 71mph (assuming my speedo is right and I think it is) I'm turning 1900rpms.
What rpm is considered the sweet spot for highway driving?
I'm going to figure out the current ratio tomorrow. If you have any other ratio suggestions (from your personal experiences) I'd appreciate it. I'm a pretty spirited driver. I want performance and mpg improvements. Thanks for your input.
2005 CCSB 4x4 6.0L Harley
8" ProComp lift, 20" Rockstars, 37" Nittos, Fox Reservoir Shocks, Dual Fox stabilizers, 2008 Tailgate with camera, 4" Straight Piped (no muffs, no kitties), Nerfs, Lights, X3 tuned by IDP, CTS, Optima Red Tops, Line-X, AutoPage