When Acura redesigned its common MDX crossover for 2014, press components specified 90.9 cubic feet of highest cargo room, a significant improve above the prior MDX’;s 83.5 cubic feet. Still, anything didn’;t fairly add up. The new MDX was 2 inches longer from bumper to bumper, but height and width had decreased 1.5 and 1.3 inches, respectively. How had cargo room elevated 8.9 percent?
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Acura explained: Optimum cargo space was really 68.4 cubic feet, not 90.9 cubic feet. It explained both numbers in the fine print on its buyer website as “based mostly on [the] SAE J1100 cargo volume measurement common plus floor area amongst 1st and second seats and front seats moved forward. This figure compares much more accurately with most competitive measurements.”
That should certainly clear things up for consumers striving to find a auto with ample area to get the kids to soccer practice or cross-country for a summertime trip.
What Acura doesn’;t say is that you can not even evaluate the 68.4 cubic feet in the 2014 model with the 2013 MDX’;s 83.5 cubic feet because Acura derived the numbers from various versions of SAE J1100. SAE J1100 is a broadly adopted methodology from the Society of Automotive Engineers to measure interior space, but its roots go back more than 5 decades.
The Tower of Babel
Why is it so difficult to examine cargo room? It really is simply because distinct automakers follow distinct cargo area accounting techniques. The methodology in query, referred to as SAE J1100 Motor Car Dimensions, originated in 1973. A thorough revision arrived in 1975, and 8 subsequent versions came among 1984 and 2009, explained Neil Mitchell, a senior layout engineer at GM. But there is no consistency as to which model automakers use. Toyota said it employs the 1975 model, which it says the EPA mandates for cargo volumes that classify a automobile as subcompact, compact and so on. Hyundai explained it uses the 2002 version Honda stated it uses the 2005 edition. Chrysler, GM and Ford explained they use the 2009 edition.
6 of the 6 automakers we contacted use 4 distinct versions of the standard. The 6th automaker, Nissan, did not reply to our queries.
Honda advised us in an email from its Ohio-based engineering group that the revisions change minor.
The fundamental formula is the very same: Take a cargo area and measure the length, width and h7 Multiply it all together and that’;s your cargo room, explained Manda Mustaine, a automobile-packaging specialist in Ford’;s engineering division.
But the versions of SAE J1100 alter which spaces in a car can be measured in the 1st area.
The True World
“The inside of a automobile is not uniform,” Mustaine said. “You have wheel wells. You have a curved roof surface. It depends on where precisely you would measure.” Most measures consider an average amongst 2 lengths, 2 widths and 2 heights, she stated. That accounts for the uneven nature of interior space, at least somewhat, simply because several measurements permit relatively for, say, the curved tailgate or bulky wheel wells. But “there is potential that someone could get advantage of a prospective nuance in the surface of the automobile and say, ‘Oh, no, no, we’;re permitted to measure this level right here,’; ” Mustaine explained.
Individuals dimensions can be manipulated by seat positioning, storage nooks and more. The Acura instance illustrates this: The previous MDX was measured using the 2002 version of J1100, mentioned a former Honda representative who asked not to be named. (Acura is Honda’;s luxury division.) The redesign was measured using the 2009 model. If you measure the new MDX making use of the exact same method as its predecessor, its cargo space goes to roughly 75 cubic feet from 83.5 cubic feet, the spokesman mentioned measure it with the 2009 revision and the variety falls to 68.4 cubic feet.
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We compared photographs of the earlier generation and current generation (over) with golf clubs behind the third row. You can see that even with the difference in measurements, there is small sensible alter to cargo area.
The redesigned 2013 Toyota RAV4 has a maximum cargo room of 73.4 cubic feet and 38.4 cubic feet with the rear seats in location, important numbers in the class. When Jeep revealed specs of its all-new Cherokee SUV (which is longer and wider than the RAV4), the numbers did not appear good in comparison at 54.9 cubic feet max and 24.8 cubic feet with the seats in spot. Seem at the side-by-side photo (beneath) with our grocery bag test (10 recyclable bags filled with identical things) and the extra 13.6 cubic feet behind the 2nd row appears like it can accommodate only a single or 2 added bags in the Toyota. Which is not a massive genuine-planet advantage.
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What about seating position? Updates to J1100 through much of the 2000s attempted to clarify just in which the seats go before you measure cargo area. Some utilised a robotic seat-measuring tool. Other individuals reverted to SAE-spec mannequins with 95th percentile legs and 50th percentile torsos, Ford’;s Mustaine stated.
The result designed some consistency as to exactly where the seats go before an automaker measures cargo space, but variances are achievable.
“Can you influence issues a little bit here and there? Yes,” Mustaine said. “Just think of the seatback angle. So even if you use distinct [driving] positions, whatever you define as your seatback angle … that can have far more of a significant impact” on cargo space.
Trunk Versus Open Area
The kind of cargo region matters, also. SAE stipulates a diverse approach to measure area in an enclosed trunk in a sedan or coupe. Automakers have to fit SAE-specified blocks that simulate luggage parcels into the trunk and add them up. But the open spaces in SUVs, minivans, wagons and hatchbacks don’;t lend themselves very easily to these blocks, and which is why the SAE and regulators invented the length/width/height calculations, GM’;s Mitchell explained.
That signifies you cannot compare a sedan’;s trunk with a hatchback’;s cargo area and declare one more substantial than the other utilizing only SAE cargo specs.
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Consider the Ford Emphasis (above) as an illustration. It comes in sedan and hatchback type. The hatchback’;s cargo region behind the second row is rated at 23.8 cubic feet whilst the sedan’;s trunk is rated at 13.2 cubic feet. Hunting at the pictures it is challenging to see exactly where the 8.6 additional cubic feet would come into perform in the grocery shop parking whole lot. Stacking objects above the prime of the rear seat could be dangerous to passengers.
“In general, the enclosed-trunk method yields a result about 10 to 15 % reduced than the precise volume of the trunk due to the fact its purpose is to represent the usable cargo area for real issues owners will want to pack,” Honda’;s engineers advised us.
The Bottom Line
At the finish of the day, automakers don’;t have to stick to SAE tips when they publish cargo volumes. “If you seem at the code of federal laws, they state which process you are supposed to use when you seem at [interior] volume,” GM’;s Mitchell said. “But then you can measure it any way you want and use it in your advertising.”
“SAE is not a governing physique,” Ford’;s Mustaine mentioned. “There is no advertising common that is required by law.”
All 6 automakers that responded to our questions stated they follow SAE guidelines. Numbers can lie, so deliver some salt and make confident you stack up our true-world cargo images alongside individuals numbers when carrying out your investigation.