Auto makers have fought horsepower wars since the day the world's second horseless carriage was created to compete against Karl Benz's 1886 original.
For almost as long, people have used the horseless carriage to tow things. But towing
wars are a much newer phenomenon.
"Until the 1990s, the trailer weight rating [TWR] was just another number," says GM trailering engineer Robert Krouse. "Pickup and SUV drivers cared about it, but they were off by the side." Then personal-use pickup and SUV sales started to take off. TWR became a key marketing attribute, he says, "and that's when you started to see a big escalation in capability."
Even more recent is the creation of a Society of Automotive Engineers (SAE) technical standard to ensure a common basis for auto makers' TWR (and gross combined weight rating, or GCWR) claims. The document was first published in 2008, but not until the 2011 model year did the first auto maker – Toyota – commit to SAE J2807. Most other makers of large pickups have only now followed suit.
Previously, each auto maker had its own test procedure for determining this number that has become integral to marketing a class of vehicle that also happens to be one of the industry's most profitable. Even if auto makers didn't push the envelope for the sake of "best-in-class" marketing hype, consumers could not previously compare ratings on an apples-to-apples basis.
Toyota actually had to trim its tow ratings when it first adopted J2807, but was able to tout its ratings as more credible. Since then, Toyota and its competitors have upgraded their trucks' capabilities to ensure TWRs continue to escalate, even as they adopt the more stringent standard.
The "sexiest" part of the standard is the highway grade-ability test, which is based on an actual road in Arizona (State Route 68, a.k.a. Davis Dam Grade) that climbs 950 metres over 18 kilometres.
In simple terms, the vehicle must accomplish the ascent at a specified average speed, with the A/C full on, without
mechanical distress, at a minimum ambient temperature of 37.8C.
That said, the vehicle handling requirements are the most rigorous aspect, says Krouse, who chairs the committee of auto and trailer engineers that created the SAE standard. Light-duty trucks typically used for towing today are more powerful than those of 25 years ago and owners can tow at higher speeds. "Getting up the hill isn't the big challenge, it's keeping the vehicle under control."
There are tests for cornering, braking and sway control, as well as for acceleration and ability to launch on a grade.
While the J2807 hype is framed in the context of pickups and large SUVs, the standard also applies to passenger cars, minivans and CUVs.
As fuel-economy standards tighten, Krouse can see people downsizing their tow vehicles: "We are going to see more
people towing their boats with an Equinox than with a Suburban," for example. "If the customers pay attention to smaller vehicles, the manufacturers will, too.
"Whether that translates down to passenger cars," he says, "that may take longer."
Here are some passenger cars and smaller CUVs with higher tow ratings than you might expect. Note that these are the maximum ratings and may not apply to all versions of the given nameplate (it may depend on which engine), and they may require a suitable tow package and/or a braked trailer. Do your research.
Mouse over the bars to see the exact figures
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