cargo cross bars vs range

[nc10]

On a recent consumer reports podcast (Talking Cars, 3/7/22), they mentioned the additonal drag caused by even empty cargo crossbars was significant, causing a 5mpg loss on Nissan Altima, and a 2 MPG loss on a Toyota RAV4. Has anyone seen similar data for EV's? I guess we'd expect a few % range loss with even empty cargo bars installed on the R1T/S?

"We did fuel-economy tests at highway speed on a Nissan Altima and Toyota RAV4 with a roof rack, a tail-hitch rack, and a rooftop box. Carrying two mountain bikes on the roof had the biggest impact. The Altima lost 13 mpg, going from 46 mpg to 33 mpg. The RAV4 lost 7 mpg, dropping to 32 mpg from 39 mpg.
There’s even a loss when driving with an empty roof rack: The Altima dropped 5 mpg, and the Toyota lost 2 mpg. The Nissan lost 12 mpg with the bikes on the hitch-mounted rack, while the RAV4 was down only 5 mpg. The bikes stuck out beyond the sides of the sedan, which created extra drag. They were mostly hidden behind the wider, boxier RAV4’s bodywork.
The rooftop box resulted in a 9 mpg decrease for the Altima and a 5 mpg drop for the RAV4.
Overall, the aerodynamic drag doesn’t hurt the more boxy RAV4 as much as the sleeker Altima."

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[kylealden]

Anecdotally, Model 3 drivers reported a ~5% loss from empty crossbars, and those ones are pretty aggressively aerodynamic. I'd expect similar from the R1T/R1S rooftop bars.

That said, I'd expect the R1T bed crossbars to have a negligible impact; they're already pretty much in a "negative space" as far as airflow is concerned.

On my Model Y, I see up to a 30%+ hit from a rooftop box or from hitch-mounted mountain bikes (which are more or less a parachute aerodynamically), especially at speed. The best way to carry bikes is probably going to be in the bed of the R1T (with a tailgate pad).

 

[aAlpine]

Seems that Rivian designed the bars to be as aerodynamic as possible. Also suuuper easy to remove, collapse, and store if not in use.

Regarding range loss for EVs, I'd expect that the impacts from poor aerodynamics to be more severe than for ICE vehicles given the efficiency of electric powertrains. For the R1T/R1S, possibly not as bad as something slippery like a Tesla.

 

[Inkedsphynx]

If you've got nothing on the crossbars, I'd strongly recommend popping them into the gear tunnel and not leaving them installed, especially since that process should take all of 30 seconds.

 

[Mcdubjr]

Honestly… I like the way they look on the back. I’ll take the slight range loss most of the time.

 

[SANZC02]

I have always removed crossbars from my vehicles when not using them. At least with the Rivian they will be quick to add and remove.

You can hear the wind noise, less for some and more for others, when they are on so you know they are causing drag. Removing them makes for a quieter ride and better mileage.

 

[nc10]

Lots of quick feedback. Thks

 

[Dark-Fx]

It's pretty significant on my Polestar 2 at highway speeds.

 

[andisimose]

Removing the cross bars on my VW Atlas is painful, but after reading this thread I will be promptly removing them to see how accurate this conversation is. I need all the MPG I can get for the next year.

 

[OverZealous]

Honestly… I like the way they look on the back. I’ll take the slight range loss most of the time.

I think it makes sense to move them if you are taking a long trip, better to get the most range you can. But I agree, I always like the way crossbars look on the R1T, and I usually prefer them on SUVs, so I'd probably leave them on most of the time for local driving.

I might be tempted to leave them at home for the R1S, though, since it's got such a clean roof line. Like others have said, at least it's easy to swap whenever you want!

 

[lostpacket]

If I remove the crossbars when not in use how will anyone know I am super into looking outdoorsy?

 

[Speedrye]

Wow, I never knew bars were so bad. On my daily driver sedan, I track mileage pretty obsessively and there is no measurable mpg hit with the roof bars on vs. off. They're a nice airfoil shape, but I was surprised as they're a bit noisy, so they must be increasing drag.

 

[thrill]

If I remove the crossbars when not in use how will anyone know I am super into looking outdoorsy?

The clothes make the (wo)man!

 

[Max]

with outback, you don't even have to worry about storing them when not in use:

 

[SANZC02]

with outback, you don't even have to worry about storing them when not in use:

That is a slick design.

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