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Roof racks make a difference in MPG!

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Old 07-06-2011, 09:50 PM
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Roof racks make a difference in MPG!

I took some vacation off to go see my mother 240 miles away. On my way there, with my Yakima roof-bars and wind fairing on, me, clothes, tools and a few other things that are always in my truck, I got 20 MPG doing 60MPH in 4th gear, @~ 2800 rpm. (5h is pretty useless unless the RPMs are above 2500 while in 5th).

I took my roof rack off for the return journey today. I also had everything I had before, plus a bike and about 40lbs of moose meat. I averaged probably 63mph, with the majority doing 65-67 (speed limit is 65 except going through towns.). I was able to use 5th gear more, probably 70% of the trip, with rpms being 2500-2600 rpm, even was able to pull some pretty decent hills in 5th!! on the 240 trip back, I traveled that far using 10.4 gallons, or roughly 23 mpg !

From my mom's town to a town 55 miles south of Fairbanks, I used just barely over half a tank, according to the gauge. The last 55 miles is 90% hills, most 6% grades. Also had my window and rear window open. the entire way

So, wow, roof-racks make a difference! I wonder if its the wind-fairing that is the worst. Perhaps if I just had the bars it would be a little better (17.5-18 mpg city, no faster than 55 mph). I'm sure weather factors in some too, but there didnt seem to be a head or tail wind either direction. Mainly cross-winds both ways (nothing huge)

Last edited by toyota4x4907; 07-06-2011 at 10:02 PM.
Old 07-06-2011, 09:58 PM
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Also, these are probably my favorite mountains on this trip. they are always so gorgeous when its sunny, regardless of the season. I wanted to take more but realized my camera's battery was dead and I had forgotten its charger at my house :\



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Old 07-06-2011, 10:38 PM
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id love to go play in alaska for a summer. it looks really nice. but i'd be long gone before winter haha
Old 07-07-2011, 12:48 AM
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yep, get rid of the air brake on the roof and mileage goes up

I miss alaska...except for hitting the frost heaves when you are half awake
Old 07-07-2011, 05:46 AM
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Just bought a '95 4Runner, already love it- It came with Yakima bars on top and the front one's situated right above the sunroof air break and above 35 mph it sounds like someone's blowing on an old milk bottle. (end caps are on bars) At first I thought it was a factory issue, but a friend pointed out that it probably is an issue with the wind running weirdly under the bars- through the air break. Toyo4x4907- do you just have bars up or do you have accessories on your bars that adds more wind resistance (and thus detracts from mpg)?
Old 07-07-2011, 06:12 AM
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I have Yakima bars and a bike rack on my pickup truck and don't notice much of a mileage difference. Whatever I lose to the racks is probably made up for by having a camper shell.
With the 22RE and 4 speed transmission, I have noticed my mileage drops considerably when I drive at 65mph and above, so I try to keep it about 60mph unless I'm in a hurry.
Old 07-07-2011, 06:57 AM
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In addition to my 88 4Runner, I have a 2005 VW Jetta TDI wagon. About 6 months ago I drove it from Chicago to NM with crossbars on it and a Thule box on the roof. Prior to the trip, I typically got 42-43 MPG in suburban Chicago. On the drive out with this stuff up top I got 38 MPG. After getting here I took the Thule box off but left the cross bars on. My mileage was 41. I got sick of hearing the wind noise above the sunroof so I took the cross bars off. Now I am back to 42-43 MPG. So I do believe that having crossbars on the roof does cut your MPG.

mark
Old 07-07-2011, 07:03 AM
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My gf's 99 Jeep Wrangler gets about 14.5mpg (she has 33" oversized tires, not regeared). When she had her roof rack on it she got a whopping 8mpg and it was impossible to hear anyone speaking inside the cabin.

Granted it's a Jeep and a soft top...so its to be expected lol
Old 07-07-2011, 08:02 AM
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Face it, our trucks have the aerodynamics of a brick (and that Heep has aerodynamics of an outhouse) but for the time they were designed, it was the best they could do. You go and add other things to the silhouette of it, it will affect the mpg's.
Old 07-07-2011, 12:51 PM
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Originally Posted by ocdropzone
yep, get rid of the air brake on the roof and mileage goes up

I miss alaska...except for hitting the frost heaves when you are half awake
But the air brake helps me stop quicker

Right around Healy, mainly north of it, the road is TERRIBLE! Full of the frost heaves, patches that have cracked and warped. Every year they try to fix it, every year it gets worse. oh well.
Originally Posted by coupstar
Just bought a '95 4Runner, already love it- It came with Yakima bars on top and the front one's situated right above the sunroof air break and above 35 mph it sounds like someone's blowing on an old milk bottle. (end caps are on bars) At first I thought it was a factory issue, but a friend pointed out that it probably is an issue with the wind running weirdly under the bars- through the air break. Toyo4x4907- do you just have bars up or do you have accessories on your bars that adds more wind resistance (and thus detracts from mpg)?
I have the bars, wind fairing, and my Hi-Lift jack with the base taken off. During the winter I use my ski/snowboard attachment. I usually take it off after snowboarding, but sometimes forget for a few days / I dont go by MPG during the winter, only miles per tank. Even then, I dont care. I just go with it.
Originally Posted by wii_tarded
Face it, our trucks have the aerodynamics of a brick (and that Heep has aerodynamics of an outhouse) but for the time they were designed, it was the best they could do. You go and add other things to the silhouette of it, it will affect the mpg's.
I'm not complaining. I wasnt expecting more than 20 mpg with the 33" tires. This is the first long highway trip I have taken with my 33" tires.
Old 07-07-2011, 03:57 PM
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I can relate to this. I've got a wilderness rack on mine (60x48) with a 33" tire up there, talk about a wind break.
Old 07-07-2011, 06:28 PM
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the fairing is a HUGE wind break. usually when i come back to bismarck from jamestown (100 miles) and the wind is coming towards me i have to take the fairing off otherwise i will keep shifting into 3rd all the time, sometimes even on a downhill. sure its louder without it but it doesnt have to shift as much. speed limits are 75 here btw
Old 07-07-2011, 08:06 PM
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You guys are funny....its like you just discovered the world isn't flat. Yes, going 60 is better on mpg's then going 80 and not having a rack is b/t 3-5mpg better.

I do think though that the fairing actually not only helps with reducing wind noise but also with mpg's b/c it creates better aerodynamics directing the wind over the bars vs. having the wind cause all sorts of turbulance, ofcourse I have not tested this theory.

Of season I drive with the bars and fairing on all the time, spring/summer with a big cargo box....yup, mpg's suck, I don't even keep track. Long trips (Seattle - LA) I take the bars off, keep my foot out of it and get 23mpg's or I go for broke and barely get 19 (with bars off too).

Don't forget...lifts, big tires, slider/bumpers, etc (basically more weight) all equal worse milage. I can do 3k in a wknd sometimes so I try to keep mine as light as possible and not run big tires. I also over inflate my tires too and stay on top of tune ups.
Old 07-08-2011, 12:28 AM
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I had a bike rack and roof rack and 600 plus pounds of stuff. I some how got 27 mpg one tank drving from CA to NM
Old 07-08-2011, 03:58 AM
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wish I could maintain 60 mph at 2800 rpm in 4th. I'm usually closer to 3100. but then, I do have a veezee, and I can pull pretty well in 5th.... even with 33's . Well.... I could before my rig croaked on me.
Old 07-08-2011, 08:26 AM
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flog them and pour in the gas

Originally Posted by michalik_piotr
You guys are funny....its like you just discovered the world isn't flat. Yes, going 60 is better on mpg's then going 80 and not having a rack is b/t 3-5mpg better.

I do think though that the fairing actually not only helps with reducing wind noise but also with mpg's b/c it creates better aerodynamics directing the wind over the bars vs. having the wind cause all sorts of turbulance, ofcourse I have not tested this theory...
Having an excess of power, especially torque, makes a vehicle less susceptible to fuel mileage decreases when dealing with weight and aerodynamic changes. Trucks and 4-runners from this era just didn't come with the kind of power they have now. 22R/RE especially.

I learned an interesting thing back in the early 90s about this. I lived in WYO during the 80s and followed a smallblock around everywhere I went. Gas mileage was what it was. Didn't much matter whether it was flat ground or wind and hills.

After I moved to Denver I got a little Honda civic with a 1500cc 4-banger. Little mofo was great in Denver. Great mileage, quick to come up to speed, awesome brakes--great city car. I had a Thule roof rack with fairing. Took a long trip up to Wyo one summer. I was rowing the shifter between 3rd and 4th the whole time, flooring it at over 4K RPM and still couldn't hold 75 lots of the time. Wind. Lo-o-ong hills.

That car relied on being lightweight and very aerodynamic (for the times) in order to perform well with a tiny little engine. It had no torque. One person in it and no roof rack and it was plenty powerful. But you could notice having 4 people in it and you could definitely notice that roof rack. It was work to keep it at speed and the fuel mileage went way down. I remember that I would get 35 mpg in Denver even driving like a nutjob, but on that Wyo trip the average was like 23.

People up in Big Wyo; when they buy vehicles get the most powerful setup the model comes with. If there's an H.O. engine, they get it. Fuel mileage may not be great, but it doesn't vary much. And they aren't flogging the thing the whole time.

Flog a vehicle and it will get crappy mileage. Common sense. Luckily, flogging a japanese engine from the 90's typically will not harm it very much. They seem to like it
Old 07-08-2011, 09:45 AM
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^^amen
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