Better Gas Mileage by lowering?

Slick · June 29, 2004

So here is a question......I lowered the back of my truck 2" with shackles. I went on a 300 mile trip afterwards and got the best gas mileage ever with my truck! Could the aerodynamics of the truck gotten better? Any thoughts?

Supurban · June 30, 2004

Drag can be produced on virtually every surface of the vehicle. Things like mirrors, door handles and luggage racks can disrupt airflow and add drag.

I'm not going to even mention the tailgate thingsince this is totally overdebated anyway.

The undercarriage of any vehicle is filled with numerous features that cause turbulance. Wheel wells, spaces between the frame and the body, and the distance to the ground can create drag.

Not knocking 33s and lift kits, but these increase the front profile of the truck which makes it harder to push the truck through the air. Up to 30 mph, this is not that big of a deal since the engine is mostly fighting the vehicle's weight. But over 30mph, increased speeds rapidly increase wind resistance.

So if you drive a stock truck, you've already got a lot of surface area facing forward - if you drive with Super Swampers and drive 80mph everywhere, then your mileage is probably going to be even lower.

Most race cars have plating underneath that not only protect the components from track debris, but also smooth out the airflow under the car. I think Lexus ran a commercial that they did the same thing on the new LS. This also helps reduce wind noise to some degree.

So lowering the truck might cleanup the airflow enough to improve your mileage.

BLKESC · July 2, 2004

If the wind was at your back, then you really will get good mpg.

snoman · July 2, 2004

A good bit of the drag is from under the truck as there is a lot of turbulance under there. Lowering it will reduce air flow under there and reduce drag which would be reflected in MPG. (one reason GM 4x4's generally do a lot better than Fords and Dodges because they are closer to the ground stock to begin with)