how much does my roof rack affect my mileage/MPG

[MetroMPG]

FYI, removing the roof rack (including cross bars) from my brother's '05 Pontiac Montana was good for a 2.8% improvement in fuel economy at 55 mph / 88.5 km/h.

In MPG (US), from 32.8 mpg (racks on) to 33.7 mpg (racks off).

This was determined with cruise controlled, bi-directional runs on an empty, straight, level road. (One bi-directional run with racks on; 6 with racks off.)

Of course, the faster you go, the larger the % savings will be.

[Frank Lee]

Pulled the x-bars off Moon Unit today. Should expect a 1-5% increase based on anecdotal evidence presented... so maybe +.2-1.3 mpg...

But I also swapped out wipers for shorter "braceless" Rain-X blades. 50 mpg here we come!

Even if it turns out to gain +0, the thing looks better.