View Full Version : Reduced mileage from a roof rack
arnstrb
04-08-2009, 04:39 PM
So, I added a Thule roof rack to my new (jan 09) CRV within weeks of buying it.
And quickly realized the wind noise would drive me crazy, so I dug up the Thule wind ferring I had from an older Thule rack I owned. And voila most of the noise was gone. But my gas mileage never went above 23, with a fair amount of highway driving. So this w/e, I removed it after I realized I can reinstall in about 20 minutes..now that I know what I am doing. And voila, my mileage for the first 100+ miles is now about 25.2 mpg, with no changes in
driving habit or type of traffic.
Is that decrease in mileage with a roof rack or maybe it was really the wind ferring, normal?
What do you think the most to the mpg reduction. The rack or the wind blocker.
Thanks,
Arnie
cr_vatech
04-15-2009, 08:35 PM
yes i believe roof racks decrease your mpg because they add more resistance to the shape of the car.. the more resistance, the more the engine must work to beat that resistance, ie gas you must use
good idea about removing for when you don't need it :)
hope this helped
GTCB-chris
04-15-2009, 08:44 PM
thats the reason people put covers over the beds of their trucks, the rack will add resistance, but the wind ferring will reduce that drag, but not enough. if you like the rack, and its too hard to remove and replace when needed, just grin and bear it, sorry i cant help anymore
electric V
04-17-2009, 10:54 AM
Car and Driver did the same test and there results were...
With cross bars and cargo carrier
gas milage dropped 1.9% at 35 MPH, 5.6% at 55 MPH, and 5.8% at 75 MPH
With the cross bars only
gas millage dropped 1.6% at 35 MPH, 3.7% at 55 MPH, and 4.3% at 75 MPH
Serj22
04-17-2009, 01:37 PM
Make sure you have the little trim plugs if you do pull the carrier off, There's 4 little plates that cover the screw holes to keep water out of them, and I wanted to do the same thing - take it off- but need those 4 plates, which I don't have so I need to go get them from Honda.
nissanguy8
07-03-2009, 09:10 PM
a few months ago, car and driver had an article on various things on a car that would reduce MPG, you should look it up and its really informative and surprising what their results were.
Orwell
07-16-2009, 09:07 PM
I am interested in getting a roof rack for my V, however I am debating if I should install one or not. Is it true that roof racks make an abundance of noises? Is it also true that MPG is affected when you have them? Anyone here with the factory roof rack notice the difference? Hmmm... :confused:
johnc
07-16-2009, 09:07 PM
I installed the Thule Areo bars that are the oval aloy ones... they make no noise.. you have to trim the rubber strip to the perfect length so the little tab on end caps can close completely..
I got 28.9 mpg on the first tank.. 40-60, lights, stop signs..
on the highway I'll have a kayak on top so it doesn't matter..
BTW.. on my last hatch back I installed my own tracks and the Thule bars and feet detached with a push of a button..
the factory bars look good, are thinner and less expensive than Thule Areo set up..
Malaka
08-24-2009, 03:58 PM
I'm sort of a test case, I guess. I have 2 '01's; one with Honda rack and cross bars, the other bare naked. There is essentially no difference in noise or mpg.
And I've driven each myself > 50K miles. If there is an mpg difference, its less than 1 mpg, which is within the range of difference from how much gas goes in before the pump shuts off.
I cannot tell the difference between the two from behind the wheel in terms of noise, either. The tire brands made a much bigger difference, but that's tire noise at speed which all CRV drivers are familiar with.
In terms of utility, I've used the roof rack from time to time and was glad I had it. But since car #3 is a Pilot with rack, that's the one that gets the "heavy lifting" jobs most often.
miragebass
08-27-2009, 05:08 PM
Hmmm well I've never done a roof setup on my V, but on my previous car (ford focus zx3) the roof rack really hurt mileage. I had saris crossbars and trays. The bars made a whistling between 20-35mph and reduced mileage about 5%. When I put two mountain bikes up there, mileage would drop at least 15%, sometimes more.
fujisawa
08-27-2009, 08:17 PM
a big drop in mileage is not abnormal. now, 25 --> 20 does sound like a big drop, but since measurement error is usually 1-2 mpg on each tank, it's not out of the range of possibility.
but regardless of the amount, definitely it will cause a change.
my advice is, see how often you actually fill up the interior and have to go to the roof rack. probably not often. there is also the safety concern - a higher center of gravity is not ideal - so installing the roof rack for the 2 or 3x a year you go on vacation probably isn't that bad.
on the other hand, you can do the math and see how much fuel you save - it's entirely possible you'll be like "i'm saving 200$, but that's worth it to not have to deal with this.
Orwell
08-27-2009, 09:31 PM
Yes, I can confirm that my CRV is averaging 2-3 miles less per gallon with the roof rack on, therefore, I have decided to remove it until I need it.
westham
08-29-2009, 11:21 PM
Yes, I can confirm that my CRV is averaging 2-3 miles less per gallon with the roof rack on, therefore, I have decided to remove it until I need it.
I just purchased the oem roof cross bars, I doubt if I will use them much but I just like the look.....2-3 miles per gallon seems high to me.........I'll see how it all works out.
westham
09-08-2009, 03:46 PM
I just purchased the oem roof cross bars, I doubt if I will use them much but I just like the look.....2-3 miles per gallon seems high to me.........I'll see how it all works out.
I just returned after a 220 mile round trip........California freeway mostly at 70 mph (a little at 80) with ac on.........I got 27.9 mpg. so I don't see any difference with or without the cross bars.
Orwell
09-08-2009, 05:02 PM
I just returned after a 220 mile round trip........California freeway mostly at 70 mph (a little at 80) with ac on.........I got 27.9 mpg. so I don't see any difference with or without the cross bars.
Interesting because I drove up to Yosemite twice this year (600+ miles round trip) and got about 27 mpg with the roof rack during my first trip on and an average of 29-30+ mpg with the roof off during my second camping trip.
recyclingbin06
12-31-2009, 09:00 AM
these roof rails won't reduce gas mileage will it?
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