A 2023 Toyota Tundra SR5 Double Cab, built in rear-wheel drive with the 6.5-foot bed and the 389-horsepower turbocharged V-6, is rated to tow 12,000 pounds. A base SR Tundra, wearing the same nameplate but the detuned 348-horsepower version of that same V-6, tops out at 8,300 pounds, a 3,700-pound swing inside one model year of one truck, according to a breakdown of Tundra towing figures by Cars.com. That gap isn’t a marketing trick or a typo. It’s the predictable result of an industry testing standard that ties maximum tow rating to a very specific combination of engine, cab, bed, drivetrain and axle, and dealers can only certify what’s actually on the build sheet in front of them, not the number in the brochure.
The number in the ad is a best-case scenario
Automakers advertise a single headline tow figure per model line, and it’s always the peak number achievable in the most capable configuration. Ford’s 2026 F-150 lineup illustrates the spread: the base 2.7-liter EcoBoost V-6 tows up to 8,400 pounds, the 3.5-liter EcoBoost H.O. tops out lower at 8,200, the 5.2-liter supercharged V-8 in the Raptor reaches 8,700, the hybrid PowerBoost climbs to 11,600, the 5.0-liter V-8 reaches 12,800, and only the workhorse 3.5-liter EcoBoost V-6 hits the marquee 13,500-pound figure, and only in the right axle and package combination, per Ford’s own 2026 F-150 Towing Guide. Ram’s Heavy Duty trucks show an even wider range: swap from a gas V-8 to the high-output Cummins diesel paired with the required Aisin transmission and a numerically taller axle ratio, and the maximum certified rating on a 3500 can move by more than 20,000 pounds compared to a base gas-powered 2500, according to Ram’s published 2024 towing and payload charts. Toyota’s own numbers show the same pattern working against buyers who assume 4WD or a bigger cab means more capability: the Tundra’s four-wheel-drive models actually max out lower than the rear-drive versions, and the larger CrewMax cab caps out below the smaller Double Cab.
Why SAE J2807 makes this unavoidable
The reason tow ratings are now this granular traces back to a single engineering standard. SAE International’s J2807, first published in 2008 and most recently revised in 2020, forces every signatory automaker to test tow ratings against the same physical benchmarks rather than whatever in-house method flattered their spec sheet. The centerpiece is the Davis Dam test: a loaded vehicle and trailer must climb roughly 3,500 feet of elevation over about 11 miles on Arizona Route 68 between Bullhead City and Golden Valley, starting at 100 degrees Fahrenheit with the air conditioning running at full blast, according to a technical explainer on the J2807 protocol. The same standard also requires acceleration, braking-from-20-mph and handling-stability tests at full payload, not a lightly loaded truck with a 150-pound test driver, which is closer to how manufacturers tested before the standard existed.
Ratings actually dropped once testing got honest
Before J2807 was widely adopted around 2013, several trucks carried tow ratings that don’t hold up under the newer protocol. A 2010 Ford F-150 rated around 11,300 pounds settled closer to 9,800-10,500 pounds once J2807 testing took hold, roughly a 10 to 15 percent haircut, and Ram’s 2500 Heavy Duty diesel, once advertised near 21,000 pounds, was published at 17,980 pounds for the 2013 model year under the new standard, per the same J2807 technical guide. Not every number fell: Ford’s 3.5-liter EcoBoost actually climbed from 11,300 pounds in 2013 to 12,200 pounds by 2015 as the engineering caught up to the tougher test. The standard didn’t just shrink numbers; it made them mean something specific and comparable across brands for the first time.
What actually gets certified at the dealership
None of this shows up clearly in advertising, which is where the disconnect at the dealership originates. The tow rating a dealer can legally certify for a specific truck lives on that vehicle’s tire and loading information placard and in the owner’s manual towing chart, both tied to the VIN’s actual engine, axle, cab and package combination, not the trim level’s ceiling. A buyer who walks in expecting the brochure’s max number on a truck built without the tow package, the numerically taller axle or the higher-output engine will be handed a certification thousands of pounds short of what they saw advertised. Ford, Ram and Toyota all publish configuration-by-configuration charts specifically because the single “up to” figure in a commercial isn’t something a dealer can put in writing for every truck on the lot.
The pattern across every brand is the same: advertising sells the ceiling, and the paperwork reflects the floor of whatever’s actually parked in the driveway. SAE J2807 solved the older problem of manufacturers gaming their own tow tests, but it never promised that every version of a truck would hit the number on the window sticker — only that whichever number does apply to your specific build is one you can actually trust.