426 Miles with 2 Kayaks on top

Discussion in 'Gen 2 Prius Main Forum' started by john1701a, Aug 22, 2006.

  1. john1701a

    john1701a Prius Guru

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    It was an interesting trip from the Twin Cities to Northern Minnesota and back. The only highway driving I had done before this was when I first bought the 14-foot kayak. Those 40 miles were quite painless. Efficiency barely dropped at all. It was above 50 MPG the whole drive. But on this trip, MPG tanked (so to speak).

    Adding the 12-foot kayak wrecked otherwise impressive hydro-to-aero shape from just the one on the roof. Between that void the two created and the increased surface area, I got to find out just how well Prius worked under extreme conditions. The result was 36.4 MPG for the 279 mile measurement taken from the same pump in both directions. That's not too bad... but sadly quite a bit lower than usual... though still high enough to make non-hybrids jealous. The other numbers are unfortunately buried within the prior and forthcoming tanks, so I won't be able to determine what the entire 426 miles provided. But you'll certainly be able to see the negative hit in my monthly statistics. Oh well. The resulting vacation enjoyment was definitely worth it.

    What I found most interesting was the difference between 60 and 70 MPH. The Multi-Display only indicated a 1 MPG change. Apparently when you are going that fast with so much on top catching the wind, speed isn't as much of an influence as you'd think.

    I was pretty darn happy with the way the roof-rack performed too. Though, I did discover that I hadn't tightened the clamp enough. So the brief heavy pouring rain lubricated the surface and helped to push the entire setup back a little bit. It was no big deal. On the way back, I found the tighter adjustment to be no big deal. None of it moved a bit. But... it was still noisy. You get a hum that simply cannot be avoided.

    Anywho, I was delighted by the experience. Prius performed wonderfully.
     
  2. daronspicher

    daronspicher Active Member

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    John,

    I'd be interested to see someone do what you've done with the kayaks, except put them on a light weight trailer behind the car. I wouldn't think that would tax the transmission any harder than having the extra wind drag above.

    Some trailer that is basically 2 wheels, some pipe and a place to mount the kayaks should do the trick. I wonder if the mpg hit would be any different more or less...
     
  3. efusco

    efusco Moderator Emeritus
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    No photo John?
     
  4. eagle33199

    eagle33199 Platinum Member

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    Thats pretty much exactly the MPG i was getting when i moved up here from cleveland... mid to high 30's over a number of tanks... of course, in addition to the kayak, the Prius was full to overflowing with crap the movers forgot, including a full sized recliner. It was so full, i broke my dog's favorite food bowl when i accidentally put down the wrong window in a parking lot and it fell out...
     
  5. gordonr

    gordonr Member

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    Last weekend did a 190 mile trip with 2 bicycles on top and two on the hitch mount. Mostly highway trip at 60 to 65 mph. The MFD read about 36.5 mpg through the trip. Checking my log from last year when I did a similar trip it was almost exactly the same. Other highway trips over similar terrain without racks have been in the 47 to 49 mpg range. When on the highway you can "feel" the added resistance. I don't have any long trips with hitch only use, but it seems like less of an impact at higher speeds.

    It appears like roof racks + stuff on top really sucks down the mileage. But like you say, the end result is still very good compared to other options.

    The scientist in me would love to quantify the mpg losses from different ways of carrying gear for both bicycles (roof, hitch, small trailer) and canoes (roof, small trailer). Anyone in the Boston area with a small trailer like the SportsRig micro trailer or Rack and Roll who would like to help?
     
  6. darelldd

    darelldd Prius is our Gas Guzzler

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    With this setup, I got combined mileage (over ~500 miles) of 47mpg. Average speed about 60mph.

    [​IMG]

    15' kayak and 16 cu-ft cargo box.
     
  7. Ron Stark

    Ron Stark New Member

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    I am a new Prius owner 2 days now and this is my first post.
    Before I purchased the car I made sure I could put my kayaks on it without caving in the roof. It appears I can.
    How are your racks mounted to the roof? Has anyone use a Hullavator system ( a TULE product) on the Prius. I plan on using Yakima mounting system (bolt on mounts) and Yakima cross bars.
     
  8. Optimus

    Optimus Member

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    I think the real question is....

    where on earth did you find open water up here besides Lake Superior and the rivers? Most all inland lakes are still frozen over thanks to a less-than-wonderful spring. I can only think of a couple areas on inland lakes that have open water, and they are pretty small areas such as shallow spots and sections of high current.
     
  9. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I think you just found the secret how some Prius reviewers were driving to get that kind of MPG.
     
  10. john1701a

    john1701a Prius Guru

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    Lots of people ask that very question. Details are in the User-Guide.

    There's some beauty shots too... here, here, and here.

    .
     
  11. Optimus

    Optimus Member

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    to answer my own question, it would have helped had I noticed the original post was 1 1/2 years old... thus you weren't actually kayaking in Northern Minnesota recently.....
     
  12. tkil

    tkil New Member

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    I'd advise against permanent mounts, unless you really do use them all the time. They have a huge hit on aerodynamic drag (and thus MPG).

    I have a pair of 48" Yakima bars with Q towers and clips. They pop on or off in just a few seconds, and are rated for the typical 150lb / 70kg. I've put multiple bikes on there, as well as things like ladders -- although the latter knocked 20% off my MPG. (That was enough to get me to pull over and rearrange things inside the car so I could take it down for the next couple hundred miles!)

    A pic from when I loaded up lots of Ikea stuff from Tempe, AZ, and drove it up I-17 then east on I-40 to Albuquerque, NM:
    2005-12-22-packed-prius

    Either way, enjoy the car!
     
  13. Betsy Morrigan

    Betsy Morrigan New Member

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    Aloha John,
    I really want to open your User Guide but can't. I just got a 2005 Prius and want to learn more about it. I have a Mac computer and there's no "right click." Is there a secret here? your User Guide looks great...just a question of opening it!
    Thanks,
    Betsy
     
  14. ewxlt66

    ewxlt66 Active Member

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  15. john1701a

    john1701a Prius Guru

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    The instructions listed were provided by Mac users, sounds like someone needs to supply an update.

    The PRESS-N-HOLD on the link should do the trick.
     
  16. maestro8

    maestro8 Nouveau Member

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    I know this post is years old, but I just wanted to point out that it's very unlikely that an unladen rack could create a "huge hit on drag". Drag is directly proportional to the frontal area an object presents to the wind, and most racks have a very small area in comparison to that of the rest of the car.

    Since mileage is determined by many factors (weather, terrain, driving habits, tire pressure, etc.) it's tough to say that one and only one factor is the culprit... but when something's markedly different, like putting a rack on the car, it's easier for one to scapegoat their lower mileage on that difference. I'd say the "huge hit" here is psychological.
     
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