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2017 prius prime roof rack MPG impact?

Discussion in 'Prime Accessories and Modifications' started by Kurama, Apr 19, 2022.

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  1. Kurama

    Kurama Junior Member

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    hi all,

    for those of you with the prius prime plug-in and a roof rack installed, have you noticed any significant impacts on the sound levels/MPG performance of the vehicle? i'm about to install a Yakima roof rack with the aluminum aero cross bars, but i'm wondering if the performance hit is significant enough to simply install it when i know that i need to use it.
    thanks in advance!
     
    #1 Kurama, Apr 19, 2022
  2. Marine Ray

    Marine Ray Senior Member

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    From Consumer Reports.

    CR Bike Rack.jpg
     
    #2 Marine Ray, Apr 20, 2022
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  3. Kurama

    Kurama Junior Member

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    thanks so much! this is exactly for what i was looking. looks like i'll install it when i need it. :)
     
    #3 Kurama, Apr 20, 2022
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  4. MTN

    MTN Active Member

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    For any vehicle, only install when needed (if not often) - or for the 'season', if that applies.

    We did recently manage 57 mpg per the car's display, on a round-trip to Joshua Tree (~500 miles), including the full battery usage, with a Skybox 16 and loaded down Prime. I did keep it 5 mph lower than our standard highway speeds, though (65-70). Previous trips with a bare roof were 65 mpg, at the higher speed (70-75), for comparison.
    The bare OEM racks also produce noticeable wind noise and I'm happy to take them off and on for when we need them.
     
    #4 MTN, Apr 20, 2022
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  5. Kurama

    Kurama Junior Member

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    we also have the Skybox. i'll keep that in mind. i don't have the OEM rack, but rather recently purchased the Yakima rack system. i wasn't a fan of how the OEM rack system appeared, tbh. :)
     
    #5 Kurama, Apr 20, 2022
  6. PianoBench

    PianoBench Member

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    hm.... 11% is a lot... I am not sure if that is the hit I am getting. Maybe I need to take off the roof rack and test it out. Ha!
     
    #6 PianoBench, May 11, 2022
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  7. andrewfez

    andrewfez Junior Member

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    I ran a theoretical calculation using drag coefficient and frontal surface area for just the naked Prius Prime and for the Prius Prime plus Yakima Skybox 16, and found that the mpg difference is around 8mpg. That's for 65mpg on a flat highway. I can try to post a link to the calculation, but I think since I don't have enough posts on this site it may not let me so I'll just post this then I'll start a new post with the link just in case!
     
    #7 andrewfez, Jun 29, 2022
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  8. Kurama

    Kurama Junior Member

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    8mpg is significant. But it's still better than what i would get in my Sienna.
     
    #8 Kurama, Jun 30, 2022
  9. andrewfez

    andrewfez Junior Member

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    Yeah, it can eat into your long distance range if going somewhere far on vacation. I'd take it off if not going anywhere.
     
    #9 andrewfez, Jul 1, 2022
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  10. W204white2010

    W204white2010 Junior Member

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    FWIW, I've put on a set of used oem roof racks with no cargo box on my 2017 prime for about 1000 miles.
    So far my mpg went down 0.1 to 0.2 mpg.

    I don't drive too crazy on local roads, but I do tend to keep the fwy cruising betweem 75~80 mph.
     
    #10 W204white2010, Jul 5, 2022
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  11. PaulDM

    PaulDM Active Member

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    OEM aero style on a non prime Prius. Perhaps 2-3 max loss.
    With roofbox (Thule weekender - not a modern box in any way) 5 loss.
    Have driven a number of miles with both bar and bar/roofbox combo.
    As per W204white2010’s comments. Max speed with a Roofbox recommendation from most people is 65mpg max and I certainly would find that driving at 75-85mph reduces your fuel economy as the EV assist doesn’t kick in over 70mph. That’s probably why they are only getting 0.2mpg. <facepalm>
     
    #11 PaulDM, Jul 5, 2022
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  12. Kurama

    Kurama Junior Member

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    for the most part, during the week, my wife uses it as a commuter, as she can reach her workplace driving solely EV, and then charge there, and drive back home solely EV, so i don't have a great estimate on just gas mileage XD. last month, we filled up once, used half the tank and drove 1500 miles. i'll log the mileage on our roadtrip to see what happens and report back. thanks for all of the responses! :)
     
    #12 Kurama, Jul 5, 2022
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