Tow Ratings Adjust for 2013 GM Pickups
By Mike Magda
We just got our first look at the tow ratings for 2013 GM pickups, and for most full-size trucks, their factory numbers will be 200 to 300 pounds lower than comparable 2012 models. And some models will drop as much as 4,800 pounds. Ouch.
As all the pickup manufacturers adhere to the new SAE J2807 towing standards this year (Toyota started early with its 2011 truck models), it’s likely that many tow ratings will fall. But for GM, its consumers are just as likely to learn that the new tow rating for select models of the Chevy Silverado and GMC Sierra will actually go up by 100 pounds for 2013, as well.
Confused? Bear with us as we sort through the numbers and hear from GM’s top truck engineer. We’ve compared the 2012 tow ratings with numbers found on the recently released 2013 GM order guides. Our sampling revealed that towing capacity for all 1500 models and many 2500 models dropped as much as 300 pounds, depending on the vehicle configuration, engine choice and axle ratio.
In the 1500 class, a two-wheel-drive Extended Cab standard bed with a 6.2-liter V-8, 3.73:1 axle ratio and the Max Trailering package was rated to tow 10,700 pounds in 2012. According to the 2013 order guide, the rating will be 10,500 pounds. A four-wheel-wheel-drive regular cab with a standard bed, 5.3-liter V-8, 3.42:1 axle and HD trailering package was rated at 8,900 pounds in the 2012 model and dropped to 8,600 pounds in the 2013.
In the 2500 class, a four-wheel-drive Extended Cab long bed with the 6.0-liter V-8 and 3.73:1 axle went from 9,400 pounds to 9,100 pounds, but the same configuration with the 6.6-liter Duramax diesel remained the same at 13,000 pounds.
“The reduction in trailer weight ratings for 2013 is a result of SAE J2807,” said Dean Perelli, chief engineer for GM trucks. “J2807 applies to all vehicles that are 13,000 pounds GVWR and below, therefore affecting all light-duty and some heavy-duty pickup trucks.”
In the past, each manufacturer set its own criteria for tow ratings. There was no uniform test procedure in the same manner that the Society of Automotive Engineers sets down for promoting engine horsepower numbers or standard procedures the EPA uses to determine estimated fuel economy. Without a common industry standard, it was tricky for truck shoppers to compare tow ratings fairly and accurately against other brands. Inexperienced truck consumers were especially vulnerable because they could be misled into believing the “maximum” tow rating used in advertising applied to every model in a particular truck line.
A few years ago, automakers, along with trailer manufacturers and towing dynamics experts from each of the OEMs, worked with SAE to establish industry standards for tow ratings. The group settled on tow-vehicle performance requirements for acceleration, driving up a grade and braking. Automakers did have the option to implement the J2807 standards voluntarily, and most said they would comply by the 2013 model year. Toyota was the first manufacturer to implement J2807 when its tow ratings for the 2011 Tundra and Tacoma were lowered.
Base weight requirements that reflect real-world towing situations are responsible for most of the ratings reductions. Before J2807, automakers referenced only a 150-pound driver as payload.
“In addition to the performance requirements, SAE J2807 applies a standard conservative approach to calculating the trailer mass, which includes two occupants, optional equipment, aftermarket trailer hitch equipment and trailer mass on the vehicle,” Perelli said.
The largest drop in tow ratings came in selected 2500 models with 5th-wheel and gooseneck hitches. For example, a two-wheel-drive regular-cab long bed with the Duramax diesel and 3.73:1 axle was rated at 17,800 pounds using a 5th-wheel hitch. For 2013, the rating drops to 14,400 pounds. A four-wheel-drive Extended Cab long bed with the diesel and a 3.73:1 axle saw its rating drop from 15,700 pounds to 10,900 pounds.
“For 5th-wheel towing, SAE J2807 assumes that 20 percent of the trailer weight is on the kingpin,” Perelli said. “Previous calculations consider 17 percent with the understanding that the GVWR and RGAWR would not be exceeded. This change, in addition to the additional mass considered above for the additional passenger, optional content and aftermarket trailer hitch equipment can have a significant effect on the new calculated trailer weight ratings for 5th-wheel trailers.”
In the 3500 class, ratings with a traditional trailer hitch were mostly unaffected; however, with a 5th-wheel hitch, most models saw a 100-pound increase. The “maximum” tow rating for the Silverado and Sierra is now 23,100 pounds. The lone model with that rating is a four-wheel-drive regular-cab long bed with the Duramax and 3.73:1 axle. A more popular model, the four-wheel-drive crew-cab long bed with the diesel, is now rated at 22,500 pounds.
“Year-to-year revisions in mass allowed the 3500 series trucks to increase the trailer weight ratings by 100 pounds,” Perelli added.
For commercial owners interested in the new 2500 bifuel models that operate on gas or compressed natural gas, those trucks will have the same towing rating as a comparable gas-only configuration when equipped with 4.10:1 axle. When opting for the 3.73:1 gears, the bifuel trucks’ tow rating will be 600 pounds lower.
“Considering the GCWR and SAE J2807, the bifuel trucks built with the 3.73 axle have a reduced trailer weight rating as a result of the shift in CNG system mass from the trailer to the vehicle,” Perelli said. “The mass of the CNG system on the bifuel truck with the 4.10 axle has no effect on the 13,000-pound trailer weight rating when compared to a similar L96 gas-only truck considering the higher GCWR. All the SAE J2807 maximum trailer weight calculations and performance requirements have been achieved to meet the maximum trailer weight ratings.”
Finally, not much else is changing on the 2013 model. A quick scan of the order guide revealed that two new colors will be introduced: Deep Ruby Metallic and Blue Topaz Metallic. Also, there’s a blackwall all-terrain tire option for the Z71 package.
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