[buraian]

Just wondering what kind of fuel consumption penalty we get for things like roof rails. I know the Forester isn't very slick anyway, but would roof rails or racks make a significant difference?

 

[FPT_RAIDER]

the rails them selfs are pretty tucked away already, but cross bars or a rack could make a bit of diff, the biggest thing would most thinkly be wind nosie. just my 2 cents

 

[Duderotomy]

cross bars and other items will have an influence. I notice about 1-2mpg less with the crossbars in place, and another couple mpg less with my roof basket.

the rails themselves shouldn't influence things too much due to their orientation on the vehicle.

 

[bellatech]

^ Yep. You lose about 1-2 MPG with cross bars and roof rack accessories.

Here is a brief summary of factors that affect your fuel consumption--

Many Factors Affect MPG

 

[dpm]

Rails and 1" difference in wheel size make for a 1mpg difference between 2.0DX and DXC...

 

[The Rookie]

Or at least enoygh difference to drop it by enough that it falles by 1mpg, as you have no decimal places it could be just 0.1mpg better!

Rough rails, about 0.2 'counts' or 0.002 on the Cd figure as a best guess from our aerodynamicist at work.

Decent front airdam and lip was what he suggested for my SF.

Simon

 

[dpm]

I was being broad. Have a look on S-UK for the figures *with* decimal places...
But I gotta reckon the rotating mass of the rims is the big part of the difference as the Urban is worse as well as the Extra-urban.