Yes. There was a difference in handling between 70 vs 75 mph. No problems at 70 mph. At 75 mph I did not feel unsafe but noticed some slight sway. It was a lot less than I experience in my high-top Conversion Van. Tall vehicles in cross-winds and gusts require steering adjustments constantly. Ford's van is sloppy but people (including myself) do it all the time.

About safety -- my Volvo is very tight -- new suspension front and rear, new brakes, just aligned it, like-new tires. I changed all tie rods in Oct and steering is tight and responsive.

Volvo empty is 3400 lbs. Plus another 500 lbs for passenger, total of 3900 lbs. The top load (Carriers) will be around 200 lbs; under the maximum allowed. I don't think it is top-heavy.

I pull trailers all the time -- I would not use the Volvo to pull anything, although people do it. I got this Volvo as the back-up vehicle plus for travel with light load like this.

I slept on it -- yes, I do feel that a hitch-based Carrier might be a better alternative. With a caveat -- the connections hitch-to-chassis will need to be reinforced. I have seen diagrams of how hitches are connected (at the end of 2 beams). No wonder tongue weight is 150 lbs. I think the load path need to be hitch to chassis closer to the rear axle.

 

Hello Henry10,
You certainly have devoted a great amount of thought to this. I am glad that you have at least considered my apprehensions. Perhaps I am overly cautious, but that is me.
I genuinely wish you a safe and enjoyable trip.

Best regards, NCdad

 

Thank you for your feedback. A few more updates to anyone following this:

1- If you recall, I said that the front of Carrier # 1 (Front) is shaking/flapping up-and-down on highway driving. On a closer examination, the nice XC90 cross-bars actually do flex, too much for my liking. I fixed that by adding another cross-bar, a good-old 1" x 1" steel angle ($ 10 at Ace Hardware) which now supports the nose of this carrier. No more flapping, which improved bobbing / swaying of the car. I use rubber pieces to separate everything.

2- I filled Carrier # 2 (rear) will almost all gear: tools, bicycle toolbox, beach chairs, games, etc. It is filled to the gills. I don't like it this way; it is not organized, and I think the top-opening has a lot to do with it. If the opening was on the rear + shelves things might be better. But the fact is that its 8 cu.ft. capacity is not enough.

3- Yesterday, I drove for 100 miles highway with 550 lbs people and cargo. The numbers are 20 mpg at 70 mph, and 21 mph at 67 mph. It drove very well, no problems with handling, braking, sway, etc. Suspension and steering is the same. The rear test will come this weekend on 2000 miles trip NYC to Iowa and back, with 700 lbs (people and cargo).

4- The rear of the car has dropped some. I actually did not measure it, but I figure maybe 1". think I will try some spring helpers. Wife does not like "you're gonna take it off, right?". I did not tell her that I kinda wanted this as permanent fixture, although this setup is not too helpful for 2-3 hour trips. 9 bolts and it's off.

5- On the hitch-mounted Carrier. Coincidentally, I am planning to do the same for my conversion van, just a little larger -- 60" wide, 48" high, 24" deep. Plus add a 4- or 5- bicycle rack on top. It would be nice to be able to switch it from one car to the other, but at approx 600-700 lbs weight, that is too much for the Volvo. Plus this would also be about 12" higher than Volvo's roof (not counting bike rack, which has little or no aerodynamic drag).

 

This is an update with the two Roof Carriers, NYC to Iowa and back, total, about 2200 miles.

1- MPG: averaged 20 mpg for the trip. I estimate my roof load to have been at least 200 lbs. 2 parents, 2 kids in the car. Highway driving mostly at 68-70 mph, but at some isolated instances at 75 mph, 80 mph or even more. No issues at all with the roof rails, cross bars or carriers themselves, except some discoloration of spray paint. This happened at the top corners of Carrier # 2, which is the boxy one, i.e. no curving / shaping to help with drag. This is an indication of which spots were hit the hardest. The $ 34 Patio Storage Box held up very well. Roof rails / roof structure handled it without problems.

2- Combination of rains and strong winds dictated that my safe speed was not to exceed 55 mph, under wind + rain conditions. This was on the westbound travel, for about 150-170 miles, approx from Cleveland (Ohio) to South Bend (Indiana) on I-80, which runs as I-90 too along this segment. On return trip, chose to go through Indianapolis / Columbus to avoid snow showers for Sat night. No problems eastbound, except Illinois state trooper in Bloomington, IL picking on NY drivers.

I see these disadvantages with this setup:

1- 4-5 MPG penalty, from my 24-25 mph highway with load. Fuel economy really plummets for anything over 70 mph.

2- Although no problems on dry condition, car handles a lot worse in rain and wind combinations.

Benefit: the additional 37 cu. ft. (outside the cabin), really free up the space. For long drives like these, taking small naps means better safety too.

Next time, I will install 2 hitch-mounted Storage boxes, and have a bike rack (4 bikes) on the roof. Hitch-tongue weight will be about 300 lbs, and I will be attaching/reinforcing the hitch on the underbody frame / beams., not where the hitch-makers tell you to.

 

Added storage volume is 15 + 8 = 23 cu.ft., not 37. Sorry.

 

Glad you made those racks and found out the bolt specs as my car no longer has it's bolts and my bought roof bars were driving me crazy until I found this and can now go and get some bolts to secure them properly.
Thanks