factory cartop racks and mileage

I'm no expert on wind resistance, but I'd guess taking off the side rails would do nothing and removing the cross rails might add ...oh, half a mile per gallon. Increasing your tires' pressure and leaving windows closed would do a lot more than this. There's a lot of hype about wind resistance. I recall forty years or more ago when Plymouths had huge whale fins on the rear end, and the hype was that they increased stability on the highway. Some engineer fired back that such a thing was indeed true....but only when the car reached 180 mph. : -)

Good point on properly inflated tires. Thanks for the reminder.

I agree with Mack on the estimate for fuel mileage improvement if you remove the cross rails. You would get more benefit from inflating the tires properly, or better yet, 4 or 5 PSI over the pressures listed in your owner's manual.

It will improve the wind resistance - but probably not enough to measure easily, well below the 'Signal To Noise Ratio' of changing road conditions and driving styles. The cross sections are too small.

The under 0.1 MPG gain (probably closer to 0.05) could as easily be attributed to a few aggressive launches at a green light.

You want to see a change, make sure your tires are properly inflated, use cruise control whenever you can to squeeze the most out of each gallon.

And figure out what your max MPG speed is. Some cars get great MPG at 65 MPH with the engine still in the fat part of the torque curve, but take a huge MPG hit when you go past a critical speed like 75 MPH.

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I've only had the vehicle for 2-3 weeks. The best mileage I have achieved to date is 24. That was driving at 55 in cruise control. Interestingly, it was a hilly part of the state, too. The worst mileage has been 18 when I made a made dash to the big city for an opera.

I have switched to synthetic fuel. In the past I improved my pickup's mileage 1-2 miles using synthetic.

It's hard to drive 55-60 when everyone else thinks the posted speed limit is 75-80.

Another way to save gas has been the use of a gps. I drive a regular route to 11 different locations. When I planned it myself, the route was

204 miles. With the gps, it dropped to 164. I'm usually pretty good with maps, but the gps "saw" a different approach to the route and I am still amazed at being outsmarted this time by it.

Thanks for the tips, by the way.

Saw an article yesterday about an informal study of 81 randomly chosen cars, which found that 80 of them had tires underinflated by at least 6-8 pounds.

Gotta be careful with the cruise control. My current and previous cars got worse gas mileage using cruise control on hilly roads. Obviously, cars can't see a steep hill coming. Often, when the decreased speed is sensed, the cruise control practically floors the engine to compensate. I'm better off adjusting very gradually with my foot. Otherwise, I was losing 2-3 mpg on certain long trips where steep hills represented an hour of the route.

With A/C, only an idiot would have the windows open.

I noticed this as well. Will be more careful, and thanks for the reminder.

PopularMechanics.com may have an article about fuel economy factors, and I think roof racks can cut highway mileage by as much as 5%.

And only Canadians with a bad attitude would run the air conditioning when it's not hot outdoors.

Chevy Chase reported a 10% drop with Granny on the roof rack.

And I get the best mileage on days when I don't drive.

On steep hills it's much better to drop out of cruise control, drop out of Overdrive - Second if you have to, and manually make best time up the hill without having to floor the pedal. With the pedal flat on the floor the mixture will go rich and your fuel mileage goes right down the tubes. And if an automatic transmission keeps hunting betweeen gears, that is a lot of added wear and tear - drop it down a notch and find a comfortable speed.

Wow, that's a new one! When did they invent synthetic fuel? ;-P

No it's not, just get over to the right and let the jackrabbits go around you. If you park in the left lane at 55, be prepared for some rude gestures and possible full-on retaliation.

A shorter route is another way to save gas - unless it's the hilly route. Or the 'always has heavy traffic' route, and you are in a peak traffic period. It's always good to do a 'sanity check' with a map before blindly following GPS suggestions.

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