We just completed a 1300 mile round trip from Philadelphia to Mount Tremblant Canada. We had 2 kayaks that we carried on a Thule roof rack with one set of Thule brackets and one set of Yakima brackets attached to the Thule rack. I read most of the treads in the forum before settling on this set-up. I purchased the full rack setup from EMS we already had the 2 sets of Kayak brackets. The bottom line on this is that I was happy with the racks, the installation process, and I had no problems. The racks once installed were rock solid. I did install them a few days before the trip and I retightened them each day before the trip. I was concerned about some of the complaints and the thread where someone lost the rack and kayak. After the trip when I removed the racks there was no indication of any type of scratching or marking of the paint by the racks. There was also no indication of any type of denting where the clamps attach. Handling was generally excellent, most of the time it was easy to forget that the Kayaks were up there. One exception was on the way home we had heavy cross winds (25 + MPH ) we could feel the gusts and trucks passing but no problems with control. I had to get the tie-downs just right to avoid wind noise & vibration, that took some trial & error to get it right and I’m not sure I can get it on the first try next trip. The total trip was 1300 miles and 1100 of that was the trips up and back. We had the rack and kayaks on the car all of the time. I ran 60 to 70 MPH as conditions permitted on the trips up and back. Mileage for the trip was 30 MPG. I know that I saw some posts talking about 35 to 38 MPG the difference may be that I had 2 kayaks on the roof and it may also be due to the speed I was driving most of the time. To put the MPG in more perspective, this is a 2008 Prius that I purchased new in April it had 6,800 miles on it when we started the trip. My life time MPG prior to the trip was 43.4 (Total Miles /Total Gas Consumption). One interesting thing is that I’ve put over 900 miles on since the end of the trip with 2 fill-ups. My MPG for the 900 miles is 49 MPG. This is the same type of driving as prior to the trip so I can only speculate that either the trip helped with the break in period that is talked about in some of the threads and my MPG will continue to see the improvement or that I’ve just happened to have excellent conditions for the last couple of weeks. My best guess is that it a combination of the 2 and I will hopefully continue to see better mileage than before the trip but it won’t remain this good. Time will tell. I have attached pictures, hope this information helps some of you.
No actually, it's the angle. At the same speeds, my 2 in the flat position (even with the cockpits open) yield 36-37 MPG. But considering how infrequently I carry them, efficiency isn't that much of a concern anyway. It's sweet that the Prius can carry loads like that. .
The angle didn't help either, but sit on tops are HUGE boats in cross sectional area, much bigger than the two that john1701a has on his Prius. No matter which way they are on the car they are going to create more drag. I haven't done a long trip with my kayak but the shorter trips have shown very little effect on mileage, but I have a very long and very narrow boat with minimal windage.
my mpg for a 1300 mile trip was 29mpg. before that, i was at 42mpg and now i'm at 48 - 50mpg. i was carrying 2 mountain bikes on a rear hitch receiver setup. I'm temped to see if i get any better mpg with a roof rack.
These reports of mpg @ highway speeds with external loads are extremely interesting. Thanks to all. V8, I really doubt that those bike will have less aero impact on top vs. hanging off the rear. However I always prefer to have expensive bikes located (up) where other drivers cannot easily damage them.
