General Cycling Discussion - Bike Racks & Gas Mileage?

Hey,

The realization is just now hitting me that I am not getting the same gas mileage that I was getting before I mounted my new Yakima Bike Rack on my car! It seams that I'm getting anywhere from 10 - 20% less mileage out of a tank of gas! I have 2 bike carriers and 2 wheel holders (folded down) AND the Spoiler!!!

What gives? Anyone else out there have similar experiences?

Mike

I am by no means expert in aerodynamics but it would seem to me that the addition of the spoiler on the front of the rack would change the flow of wind over the car. Thus changing the wake and causing the wind to have a steeper decent off the back of the car producing more drag that the car will need to over come.
Try taking the spoiler off the front and see if it changes.

Slainte:beer:

There is alot of drag caused by bike racks, especialy roof racks. I read something a while ago, without any bikes they add 5-10% more wind drag to you're car. So this would atelast hurt your gas mileage by 5-10% min.. probably more.

My son in law drives 80 miles round trip daily to work. Says the racks not only hurt feul mileage, but add to the wind noise. Claims it's worth it though to be able to have his bikes with him when he wants to. I use a rack which is removable between trips and attaches at the back of the vehicle. I've noticed no change in feul mileage. Must be the roof racks.

Happens that way. That's why my girlfriend and I use a Saris Bones Rack: put it on take it off, no problem.

Racks will have an impact on city driving, because they increase the mass of the car. If your bikes and rack weight 100 pounds and your car weighs 2000, then your fuel economy will be down about 5% for city driving. For high speed driving (highway speeds) the vast amount of the drag is on the front of the car rather than the back (which is why so many cars have vertical or near vertical rears). Adding a bike rack should not make a huge difference for a car. For a SUV, the difference should almost be neglibile.

I've owned top mount Yakima's with wind deflector... Forget gas milage if you're going or gone this route... The wind deflector has minor affect.

I recently purchased an SUV... and a Thule 4bike outragious hitch mount rack, much easier to mount the bikes and swings out of the way for back door entry...and for those worried about milage, has little affect, because it's behind the vehicle. :)