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Just curious if you folks out there with roof racks have noticed much of a decrease in gas mileage with your roof racks. I currently have a Yakima system with a fairing (wonder if that "helps") and honstly, I didn't check my gas mielage before I installed the rack. Now I am debating putting a roof rack on my new SUV (I would hate to add to the fuel efficiency problems of an SUV!). Have you all noticed much of a difference?
 

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I also have a Yakima rack with a fairing, and I think it costs me a mile or two per gallon. With three bikes on top 2 on the back and a car load of people I saw close to a 10 mpg hit. There's a lot of variables there though. You will also notice a larger difference on the highway than city.

As someone who likes to race around in my cars, I can feel the extra drag with the rack hurting performance, so I leave it off unless I'm carrying more than one bike, which fits nicely inside.
 

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Roof racks are reported to reduce mileage by as much as 5%. I don't know what the difference is between loaded and empty. I imagine it depends on the size and shape of both load and rack.
 

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Decrease in efficiency

I have an '01 Honda Accord coupe (4-cylinder; 74,000 miles). I averaged about 28-32 mpg on a tank of gas before the rack. With the Yak rack and 2 Rocky Mounts fork mounts for the bikes, I currently get about 23-26 mpg average per tank (mostly highway), which is about a 15-25% decrease in fuel efficiency.
With the bikes up there, forget about it, my avg mpg gets super ugly.
Adding a faring helps efficiency and especially with the noise reduction.
 

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It's a Sledgehammer
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faring

I have a Thule rack, while I haven't paid much attention to fuel economy, it does make some noise though. Do the farings help in either mpg or noise?
 

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I own a VW Golf TDI. Here are my numbers:
-No Rack: 45mpg
-W/ Thule Rack: 42mpg
-W/ 2 bikes: 32-36mpg

At least I start at 45mpg :rolleyes:
 

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iedereen op de fiets
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Numbers

i have a F-250 Crew Cab Diesel 4x4. Load the bikes in the bed with mounts attached to a 2x6 and I get 18 mpg. Take the bikes out and I get 18 mpg.

Now my Volvo V-40 with a Thule on top(without a bike), 26 mpg here in South Georgia. We got 32 mpg while we lived in Vail. On a 4,000 mile round trip just after buying it (with a bike on the roof and tons of luggage), we got 26.3 mpg at an average of 72 mph.
 

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Upping the ante

nate said:
Roof racks are reported to reduce mileage by as much as 5%. I don't know what the difference is between loaded and empty. I imagine it depends on the size and shape of both load and rack.
Yes, 5% for the empty rack, but 10-20% for bikes on the rack. If you have very poor aerodynamics and low mileage to begin with, then adding a rack won't have as much impact. Cay you say "F-250 Crew Cab Diesel 4x4"? :)
 

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3 bikes drop our Civic from 34 to 26 @70-75

I've checked this several times, just for something to do on long trips. My wife's Civic coupe reliably gets 34-35mpg at 70-75, which is a conservative cruising speed on most California Interstates. The rack alone costs us about 2mpg, but with three bikes on top we can't beat 26.
 

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7eap4a said:
I have a Thule rack, while I haven't paid much attention to fuel economy, it does make some noise though. Do the farings help in either mpg or noise?
Definitely quieter, at least on my Saturn sedan.

I was also surprised at how much difference just the bare rack affects mileage at highway speeds. (Mid 30's with no rack, around 29 or 30 with the bare rack, and mid 20's with a bike on top.) Keep in mind this car is on the under powered side to begin with so, with the rack, the transmission has to shift down for all but the wimpiest of hills.

I keep toying with the idea of getting a Honda Element because it will fit our garage and, I'm told, will just barely fit a tandem on the inside. Of course, then I'll be paying a gas mileage penalty all of the time, not just when I'm carrying a bike on the roof.
 

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hehheh...

with the multimillions of dollars put into aerodynamics for TT frames...

... I wonder if the figures are any better for TT bikes with disc wheels

:p
 

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Lot's of variables. I have a Civic Hybrid. In the summer without the rack I'll get 47 to 50 mpg. With the rack it drops it down into the 43 range. With a bike on, it just sucks.

Here in Colorado they add ethanol to the gas over the winter. That alone will takem my 47mpg down to 42. Gas mileage sucks all winter. They just switched back to real gas on April 1 and my mileage is back up to 47 just in time to put the rack back on.

I've resorted to only putting the rack on when needed. It's a 2 minute pain, but worth it.
 

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Pretty big effect for me.

2006 Subaru Outback. Normal highway mileage (with rack only) is about 30 mpg.
Transporting 2 mtn bikes, 2 adults, plus car load of camping gear to Tucson in a howling February headwind, 23 mpg.
Makes me consider getting a rear hitch rack for a long road trip to CA with bikes and using a "torpedo" carrier on top for gear. They have got to be better than those bikes on top.
 

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:rolleyes: This is really a no-brainer, isn't it?:rolleyes:

If you're concerned about the reduced gas mileage, just put your ride inside the vehicle & become more aero......:eek:
 

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with a roof rack

you have one more thing to worry about... low overhang. It happens to the best of them. Remember to put the garage remote control out of reach so you don't accidentally drive in with the bikes on top.
 

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How quickly do they go on and come off?

I've been thinking about one for my Protege. Have a Saris Bones trunk rack and it's as good as any I suppose but the rubber feet are rubbing dirt into my paint if I don't keep the car immaculately clean. That doesn't fly with me very well. And with the frequency that I move my bicycle around (I take it to work to ride at lunch), I get sick of that thing always hanging off my car's rear end.
 

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For he benafit of the origonal poster, I think we should discuss why it hurts your mileage...
When you add anything to the factory lines of your vehicle, you change the aero dynamic properties. In shourt, the rack is creating drag. (and I guess weight would be a negligabel factor to)
Remember when as a kid you put your hand out the window, and felt the wind rush over it? When you held you hand flat, the air just flowed over your hand like a wing. When you put your palm into the wind, it started to really push aginst your hand, much like a sail.
By putting a rack on top of your car, you've just added "a big braud hand" if you will to the top of your car.
 

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Lost over 10 mpg

My Saturn L200 lost over 10 mpg when I put 2 bikes on the roof when driving to Daytona from Houston...quite an expensive lesson. MPG went from 27 to 15-17 highway. It wasn't as bad with only one bike, but thats still worse than my 3/4 ton Ford crewcab with the PowerStroke diesel gets! Now they'll be on a hich rack or in the car when I'm not in my truck.
 

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Trunk or hitch racks...

are better, but, with a small car,they too disrupt aerodynamics. I feel it on the highway with my small car. The acceleration at highway speed is noticeably slower with the bike on the rack.

A big car like an SUV with a rear rack probably feels the least additional drag as that spot behind the big wide butt of the car is kind of an aerodynamic no man's land.
 

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I ditched my roof rack long ago, and I suspect many other people are heading toward that, as gas heads toward 3.00 per gallon, and beyond. Cheap energy was the biggest lie that was perpetrated in this nation for 75-100 years. Get ready for euro prices for energy, and the end to recreational boating, driving, and "cruising" the boulevard.
 
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