roof rack drag?

Am a little bummed about taurus with 44 k only getting 23 mph. Maybe it got 26 before racks with saddles. How many mph drag loss for yakima racks? How much worse for saddles? They are pop riveted in because they would not hold still when I go with lots of span for 21 ft t-bolt.

I’ve thought about it…
Not that I’m the sharpest bow in fleet.

But, I’ve come up with a few things.

My Yakima cross bars come off very easily. I take 'em off when not in use!

If you lose 3 miles per gallon, say at three dollars per gallon…over 100k miles…a bit over $1500 wasted. Bummer. Will you haul your boat 100K miles?

If my math is correct, you’re gonna hafta kayak and canoe your keester off before you lose a pile of money.

If my math is not correct, I’m sure many fine individuals will rise up and point it out right away. I don’t mind correction.

I’m not sure what you riveted to what, but if you can no longer remove the rack, what if you bought one of those air dams and spun the cradles down onto the roof when not in use? Same goes if you riveted the saddles to the bar. Nice justification for round bar followers :slight_smile: If you riveted the bars to the towers, it’s a good plug for Thule. But you could still rotate the saddles individualy.

Also, for fun, one day I will test my milage with boats on roof, as opposed to boats on trailer. Mostly I use the trailer when hauling more than two, but I really must check it out someday. I doubt that the economics of it will justify the trailer, or even the tires on it, but it’d be interesting.

Well I’m sure all this is very little help, but you did ask.


Roof Rack Drag

I used to own a Taurus with a Yakima Rack, I found a similiar difference in my gas mileage… My Honda Civic is even worse! Probably a 5 mpg difference. Add in air conditioning with my Baidarka on the roof and the difference can be 10 mpg; if the roads are hilly, or it is a windy day, or if I try to go fast. Fortunately, the Civic gets about 30 mpg under the worst conditions. At least if I’m getting less mpg, it means I have a boat on the roof and I’m travelling somewhere different to paddle!

sure makes the saris line more attractiv
maybe we should buy the brand and have them made well in china?

2/10 of a mile difference with my F150
and the racks with kayaks. Not worth the trouble to take them off.

I lose a few MPG too…
I have a Tacoma, and without the rack attached it gets 26 to 27 MPG. With the rack (including the fairing) I am lucky to get 24 MPG.

I hate that fact, but I try to make it up by riding the Bicycle a little more…

I have Malones…
mounted on factory bars and they stick up. I don’t have any numbers but I remove the bars (easy to do) if I’m doing any amount of driving without the boats.

Over 10 yrs though.
I come out $1327, so same ball park. Thing is I probably do 100,000 miles in 15 years, especially if I exclude trips where I need them on. So a little less than $100 per year to leave them on.

Is the Taurus in question a V6? Efficency loss should be less with larger engines. My 1975 Chevy duely, 454 cu. in., headers, highway, gets 11 mpg. I could drag the Empire State building behind it and it would still get 11 mpg. I’ve only driven it a couple thousand miles in 8 years. It’s sort of a toy, one I’d like to sell.

Not saying it’s a bad idea to take them off when not in use.

Me, I just leave them on. Less work and it makes me feel good to see them. A little symbol of the outdoor life in the midst of the daily grind. I suppose it might be cheaper to just leave my PFD the passenger seat.

Paul Stivers.

Exaggerated Losses Evident…
Well I had my racks on my '05 Honda Civic Hybrid and with one boat (Necky Sky) I dropped from 52mpg to about 44mpg. With two boats (Necky Chatham & Looksha) I went down to almost 34mpg on a long trip…either way, 34mpg on a long trip is not bad with two boats on top, so I will certainly use the civic to take the boats anywhere non-local. However, I have recently switched the yak rak with saddles over to our Subaru Impreza 2.5RS and it went from 25mpg no rack to 22mpg with rack (sky on top 5/8 days for the tank).

Now, my IH Scout II loses no mileage with both the Chatham and the Looksha on top. What you will find is lower torque vehicles that depend on aerodynamics will of course suffer far more from the rack than will hi-torque, low aerodynamic vehicles.

And for those who are curious my IH does 14-17mpg on the freeway depending on grade. It’s fuel injected :wink:



My Honda Element, being about as aerodynamic as the IH Scout, also suffers little for the Yakima rack on top.

When you have something shaped like a concrete block being forced through the air by an IC engine, the addition of a turbulator device (roof rack) does little to worsen the already dismal coefficient of drag.

On the other hand, with a slippery shape like the Honda Insight, you are REALLY hosing up the aero situation with a roof rack, and the mileage figures show the proof.

We also own a Toyota Prius which I COULD put the racks on, and have a MUCH shorter lift for getting the boats up and down, not to mention a considerably smaller fuel bill.

But, the larger cargo area, plus higher ground clearance and AWD make the Element our weapon of choice for going to the sometimes less than perfect launch areas.


Some efficiency loss…
My VW TDi wagon drops from around 45mpg to around 40 with racks/yaks and to around 42 with racks alone (Malone). For long trips without yaks, I take the racks off. For shorter around town stuff, I just leave them there.

wear on the vehicle
One thing that people don’t often consider is the added wear on your drivetrain that roof racks cause, especially if you drive an automatic. I have probably 15 years or so of experience with racks, between paddling and bike racing. I’ve come to the conclusion that using a roof rack to carry stuff is very similar to towing. Similar drop in mileage, similar early death of automatic transmissions if not equipped with a cooler.

wear on vehicle
hmmm, hadn’t thought of that. My automatic Jeep Cherokee burned up at the roadside due to the tranny catching fire! Only automatic I’ve ever owned (and perhaps the last one too!)

Toyota with Yakima
Being an engineer type, I like to figure these things out for fun. Adding the bare Yakima racks to my 2004 Toyota Double cab costs a little less than 1 mpg on the highway. Adding a canoe changes almost nothing.

By contrast, adding a soft tonneau cover to the truck be added 2.5 mpg!

Slowing down my commute from 70mph to 60 mph netted an almost 20% efficiency gain! Thats one whole 40 mile commute (each way) each week!

Finally, the racks are super easy to take on and off so I leave them off unless in use just to avoid the dreadful wind noise (much less evident with canoe in place).


Buick Roadmaster doesn’t notice.
I get 20 mpg with saddles and J bar on or off. Warm or cold, rain or shine, highway or city. This car is so big it just doesn’t notice much. Heated leather seats are nice after a day on/in the water.


All over the place
As you can already see from the responses, some vehicles are more affected by roof racks than others.

In your case, you already know what happens. It’s too bad you can’t remove and install the rack more easily.

For carrying my short boat, I use Yakima round bars with Control Towers and Landing Pads on t-slotted rack tracks on a truck topper. The truck’s mpg did not change one iota when I added the roof rack bars, and there is no additional noise (whew). I keep those bars locked on 100% of the time, though the set-up is very easy to take on and off. Surprisingly, there is also no change in mpg even when I carry the kayak; however, I have not taken a long trip with this kayak on top, when high interstate speeds/aerodynamics would become more important than in local driving. The truck itself is not nearly as aerodynamic as most small cars, and it has a large V6 with lots of torque.

I’ve found trailering sea kayaks with this truck to reduce mpg no more than 0.5 mpg. Ditto for the three other vehicles that we’ve used to tow this trailer and kayaks (a V8, another V6, and an I6).

However, on a recent road trip in my husband’s Tahoe with roofracked sea kayaks, the additional wind drag and weight probably did reduce mpg. That vehicle usually gets 19 mpg highway; on this trip it only got 17 mpg.

Bottom line: if you want to preserve mpg, use a trailer or drive a big vehicle, neither of which may appeal to you. After all, if you drop from 40 mpg to 30 mpg when rooftopping, you’re still doing better than someone who gets 15 mpg no matter what.

Edge forward
My rack has mostly edges of flat surfaces facing forward and has little effect on mileage in a Ranger SC w/topper, 4x4 4L-V6. The biggest ding on my mileage is the ethanol blends. It would be interesting to see how close the tolerance is monitored in the blending the way my mileage bounces around between tank fulls from different brands. If they are requiring burning the stuff then let’s get the price down to compensate for lower BTUs = lower mileage and HP. If I have to burn more fuel to get to where I’m going how much benefit does it really have to the air quality?

thank you
Will take them off this nov when season is over. Wrapping string around bars makes them much quiter. Pop rivets under door frame because curvy car does not allow 4 ft span without heavy screws or rivets. Peace of mind is big to me when going 75 on freeway. No one tailgates you.

Maybe that’s why my gas mileage dropped
by 1.5 mpg on the 600 mile trip I made Sunday/Monday sans kayak. The drop was from my last 400 mile trip with kayak but with MBTE additives.

I’m getting 53mpg with rack and yak. Not too shabby. Without the yak I’m up to 57mpg. This is without the ac on which drops the mpgs by at least 6 mpgs. FishHawk