2022 Forester Sport, 38,000 miles, factory raised rails. we leave Bend on the 15th for Whitefish and then Glacier, eight days, two dogs riding in the cargo area, which means every bag has to go somewhere else. so: roof box.
i bought a used Thule AeroBlade crossbar set and a used Force XT L, 16 cubic feet, both off marketplace for 340 dollars together. the box has one cracked corner on the lid lip and the previous owner included the key, which i gather is unusual.
three questions that the internet keeps answering three different ways.
the load limit. the manual in my glovebox says one number, the sticker i can see on the rail says something else, and every forum post i found says a third thing for a different model year. does the weight of the crossbars and the box itself count against it, or is the number just what goes inside?
the noise. is a box on crossbars loud at 75 or is that just the bars by themselves?
and clearance. if i slide the box forward enough to not block the hatch, does it then sit over the sunroof and whistle? Thule has the fit guide and the dimensions on their site but nothing about which position people actually end up using.
the load limit question is the one everybody gets wrong, so, carefully.
there are two numbers. the dynamic load is what the roof can carry while the car is moving, and it is the one in your manual. the static load is what it can hold parked, which is much higher and is why a rooftop tent works at all. Subaru has changed the dynamic figure between model years and between trims with and without the factory rails, so the only number that applies to your car is the one printed in your own book for your own year. not the one on a forum, not the one on a rail sticker from a different market.
and yes, everything above the roof skin counts. bars, feet, box, and the stuff inside it. your Force XT L is somewhere around 50 pounds empty and the AeroBlades with feet are another 10 to 13, so you have already spent a chunk of the number before you put a single sleeping bag in. that is why people who load a box to the brim are often over the limit without ever suspecting it.
the limit is not really your problem though. with two dogs and a full box you are raising the center of gravity of a tall car, and the thing you will feel is the crosswind on 97 between Bend and Madras, not the roof skin bending.
i can give you real numbers on the mileage part because i ran a box on mine for two summers and logged it.
at 75 on I-10 i lost between 4 and 5 mpg with the box on and empty. at 65 it was about 2. loaded or empty made almost no difference, which tells you the whole penalty is the shape sitting up there and not the weight. the bars alone, box off, cost me about 1 mpg and a hum at 70 that i stopped noticing after a week.
the useful part of that: take the box off when you are not using it. people leave them on all summer and pay for it every tank. mine lives on two hooks in the garage eleven months a year.
worth knowing if anybody with a hybrid is reading: the hit is proportionally worse on these. i logged 38 mpg on my usual highway run and 31 with a box on, which is a bigger percentage than what Tucson is reporting, and i think it is because the hybrid is already doing well and there is less fat to lose. the engine just runs more of the time.
no advice, only the number, because somebody asks me whether a box hurts a hybrid more about twice a summer and now there is a post to point at.
back. Bend to Whitefish is 650 miles and we did it in a day with two dog stops. 26.4 mpg is my normal on that road and i got 22.1 with the box on, so right in the middle of what you two said.
the whistle was real for the first 90 miles, a thin one at anything over 68. pulled into a rest stop past Spokane, moved the box back about two inches so the nose of it sat behind the front edge of the roof instead of over it, and the whistle stopped completely. i have no theory for why that worked, i just moved it because my wife told me to.
the dumb thing i did, and this is the part worth copying down. i put the heavy stuff in the box, because the box is where the bags fit. so the cooler, the tent and the water jug went nine inches above the roof and the pillows went in the car. backwards. heavy in the car, light and bulky in the box. i could feel it in the corners on 200 south of Columbia Falls and i will not do that again.
dogs were fine. 95 degrees in Omak and the air conditioning in a Forester cannot quite handle that with two panting animals in the back, so we ran the rear vents on high and stopped more than we planned.
two questions from someone shopping for a box rather than owning one.
how much clearance did you end up with between the open hatch and the back of the box, and did it block the rear wiper or the view out the back glass at all? and what is the garage situation? mine is 6 feet 10 inches to the opening and i have a feeling that is the real constraint on this whole idea.
measured both for you. an inch and a half between the open hatch glass and the back of the box, which is enough but not comfortable, and i open the hatch slowly now out of habit. it does not block the wiper or the glass because the box sits well forward of the back edge. the Forester is tall enough that i am on the running board of the door frame to reach into it and my wife needs the step stool from the garage.
my garage opening measured 7 feet 2 inches and the car with the box clears it by about four inches, which i verified by walking alongside at two miles an hour the first time with the window down and my head out. 6 feet 10 would not work on a Forester. it might work on a CR-V, which is three or four inches lower, but i would measure your own car in the driveway with the box on before you trust any number off the internet including mine.
box came off on sunday. one thing nobody mentions: the bar feet trapped grit against the rail and left two dull marks in the paint on each side. not through the clear coat, but you can see them. clean under the feet when you take the bars off and do not leave them on in the rain for a month like i did.
