SRW towing limits

[clev]

I know that most you you are dually drivers, but there are quite of few of us SRW drivers out here, as well. I received the 2019 Good Sam Guide to Towing and thought some of you might be interested.

The Ford F350 CC, LB, SRW, 4x4, 6.7 TD has the highest tow rating. It has a max tow capability of 20,400 pounds with a GCWR of 28,400. I thought that was pretty impressive for a SRW truck.

The same configuration for Chevrolet/GMC is 17,000, no GCWR was listed

The same configuration for Dodge Ram is 16,860; again, no GCWR.

I know that all these trucks are towing beasts with superb power trains, so I don't understand the differences in max towing.

Don't shoot the messenger.

[Walker]

Braking capability may be the difference. Or a different U-joint is used and is rated lower, different axle bearing, etc.

[rynosback]

Each manufacture comes up with there own specs. I believe Ram has adopted these standards. Maybe this is why they are the lowest. But the standard that some manufactures use is SAE J2807. Which if everyone adheres to would be a good comparison between manufactures. I had read that if the ones that have not adopted it, there ratings would go down.

[rynosback]

Heavy-Duty Hodgepodge
Heavy-Duty pickup tow ratings are still in flux. The first published version of J2807 caused arguments that led to an immediate revision that exempted most of them. But a new draft version now covers pickups with Gross Vehicle Weight Ratings as high as 14,000 pounds, which brings them back in again.

Ram has certified its 2014 and 2015 Ram 2500 and 3500 products to J2807, but General Motors has not done the same with its 2015 Chevrolet and GMC 2500 and 3500 HD models.

Ford went ahead and certified the 2015 F-450's tow rating using J2807 because of its upgraded engine and substantially upgraded underpinnings. But it decided not to do the same with the carryover F-250 and F-350 lineups, which will be fully redesigned next year.

GM's new Chevrolet Colorado and GMC Canyon were certified to the new standard, so their tow ratings can indeed be compared with the Toyota Tacoma, which has been in compliance for four years. But the carryover Nissan Frontier is expected to remain outside the standard until it is redesigned.

Toyota's Sequoia SUV is J2807 compliant, but the new-in-2014 Chevrolet Tahoe/Suburban and GMC Yukon/Yukon XL are strangely not. It seems that they, too, are waiting for Ford, which won't roll out a new Expedition for a year or two.

It's harder to pin down the crossovers, minivans and cars, though. SAE J2807 test procedures apply to all of them, but these vehicles were never embroiled in the same sort of towing arms race that gripped the pickup and full-size SUV segments. Their ratings were never pushed to the absolute limit, so it's hard to imagine them changing much even when they do get rated according to the new procedure.

[Cummins12V98]

What do you think they are towing at those numbers??? Sure as HE!! aint no 5er!

Let's see some SRW SAE tow ratings with 20% 5er pin weight ratings. BTW MOST full timers with a tandem axle DRV are in excess of 20% pin. I am at 25% being 5,750#.

RAM does go by J2807 with their tow ratings. Wonder why GM has a low 23k rating for their DRW??? It's because the Allison can't hold up to more weight in the SAE tests. They made a sorry excuse they felt people really did not need to tow more than that. Wonder what they say when the new trucks come out with the new 10 speed and their ratings are magically right up there with RAM and Ford???

The 2015 SRW RAM GCWR was 23,500#.

Look up RAM towing guide it states SAE J2807 right at the top.

[Cummins12V98]

Ford was able to publish J2806 for the 450 back when the article was printed Ryan is referring to. They were NOT able to come close to RAM's numbers with their 350 so they did not participate in the SAE rating until their completely new 350's came on line. I am fairly certain all three go by SAE now.

FYI RAM does not strip down their trucks to get the carrying capacities that some are or were doing.

[Cummins12V98]

I looked up all three 350/3500 HD DRW long box 4x4 Crew 4.10 Ford and RAM and 3.73 GM.

Ford DID list SAE but "ONLY" for the DRW trucks, so take the Ford SRW ratings with a grain of salt.. Their DRW 5er limit is 27,500# that is hitch limited. Their Gooseneck is 31,300# and combined is 40k.

GM towing is 22,700# and does NOT mention SAE anywhere i could find. Their combined is 31,300#. So technically I could not tow my DRV within their ratings.

RAM lists SAE at the top of each chart 2500, 3500 and 3500 DRW.

They base their 30,100# trailer rating on 15% pin gooseneck or 5er. Tripple axle 5er will fall into that category. They have 39,100# combined.

[rynosback]

Ron, I think Ram was the first of the big 3 to comply to the SAE J2806.

[Cummins12V98]

Originally Posted by rynosback

Ron, I think Ram was the first of the big 3 to comply to the SAE J2806.

Yes and they did long before they advertised it. That's why they were always under rated compared to the others but in reality we knew that they performed as well as the others.

[Chance]

Originally Posted by clev

.....cut..... I received the 2019 Good Sam Guide to Towing and thought some of you might be interested.

The Ford F350 CC, LB, SRW, 4x4, 6.7 TD has the highest tow rating. It has a max tow capability of 20,400 pounds with a GCWR of 28,400. I thought that was pretty impressive for a SRW truck.

.....cut.....

Thanks for bringing this up. It’s not applicable to me or my needs, but was interested enough to look up the test. I’m not sure why test requirements are tougher on SRW trucks compared to DRW trucks.

If anyone knows, I’d be interested in knowing why SRW trucks are held to a higher standard.

[rynosback]

Originally Posted by Chance

Thanks for bringing this up. It’s not applicable to me or my needs, but was interested enough to look up the test. I’m not sure why test requirements are tougher on SRW trucks compared to DRW trucks.

If anyone knows, I’d be interested in knowing why SRW trucks are held to a higher standard.

Why do you say that they are held to a higher standard? The whole goal of the SAE J2806 is that you could really compare numbers as they all test them the same way.

[Chance]

Originally Posted by rynosback

Why do you say that they are held to a higher standard? The whole goal of the SAE J2806 is that you could really compare numbers as they all test them the same way.

Not sure if this is the latest, but seems to be tougher on SRW trucks on acceleration and hill climbing.

SAE J2807 Tow Tests - The Standard

Originally Posted by TruckTrend

Flat-Out Acceleration

Three tests are used to determine if a truck/trailer combination has sufficient acceleration on flat sections of road. One is a test that measures the 0-to-30-mph time, with single-rear-wheel trucks needing to reach that speed in 12.0 seconds, while dual-rear-wheel models get 14.0 seconds. There is also a 0-to-60-mph acceleration test that allows SRW trucks 30.0 seconds to reach that highway speed while DRW models get 35.0 seconds. To measure passing capability, the 40-to-60-mph time of single-rear-wheel trucks must be 18.0 seconds or less, and dual-rear-wheel trucks are allowed up to 21.0 seconds.

Making the Grade

To simulate some of the toughest conditions a truck and trailer combination will face, the J2807 “Highway Gradeability” tests take place on a well-known stretch of Arizona highway, the 11.4-mile-long Davis Dam Grade. If trucks are not tested on this specific stretch of steep road, they can be run in a simulation using a “climactic” wind tunnel. Ambient temperature plays a significant role in this test with a minimum temperature of 100 degrees required at the base of the grade. In addition to a hot climate outside the truck, the test requires the air conditioning system to be set at maximum cold, with outside air selected (not recirculating) and the fan running at full blower speed.

Once those criteria are met, the evaluation can begin on the famous stretch of SR 68 between Bullhead City and Golden Valley, Arizona. To pass this test, a truck-and-trailer combination must be able to drive at 40 mph (35 mph for dualies) and never drop below that speed until the end of the test segment at the peak of Union Pass. Testdrivers are allowed to go faster than the minimum speed requirement in the sections of the grade where posted speed limits are 55 mph and 65 mph, but there are other requirements the vehicle must still meet. Under “drivetrain system performance,” the J2807 standard requires there be no component failures, along with no “check engine” lights or any other alerts or warnings for the driver. The “cooling system performance” requirement also requires zero part failures, no error codes, no driver warnings of any other kind, and no loss of coolant fluid during the test.

[clev]

Well, I really thought that all manufacturers were required to post tow limits based on J2806. This was for the purpose of stopping manufacturers from simply posting numbers and requiring the comparison of apple to apples. If that's not true, I learned something new. And, thank you, Chance, for posting the standards.

[Cummins12V98]

Longer times are relevant to the heavier loads. The BIGGIE is the repeated hill start tests, I assume this is where the Allison was not able to keep up with the Ford and RAM trucks as this would cause the most stress.

The AISIN really pulls nice from the line on a grade even with a 35k combined load thanks to it's lower starting gears combined with 4.10's.

[Chance]

Are these the Aisin gear ratios you are refering to?

It’s interesting that the test requires five launches in a row up a very steep 12% grade within 5 minutes, and then requires repeating the same test in “Reverse”. For this test it appears that having a very low reverse ratio would also be helpful, which is not always the case. The Ford 6R140 transmission in particular has much taller reverse gearing than 1st forward gearing.

Some of the lighter-duty 8- to 10-speed transmissions are using about 5:1 ratios for 1st and reverse. That should help with this part of the test. It will be very interesting to see if the new 8- and 10-speed heavier-duty transmissions to be introduced soon have much lower initial gearing like their lighter counterparts.

[Cummins12V98]

Originally Posted by Chance

Are these the Aisin gear ratios you are refering to?

It’s interesting that the test requires five launches in a row up a very steep 12% grade within 5 minutes, and then requires repeating the same test in “Reverse”. For this test it appears that having a very low reverse ratio would also be helpful, which is not always the case. The Ford 6R140 transmission in particular has much taller reverse gearing than 1st forward gearing.

Some of the lighter-duty 8- to 10-speed transmissions are using about 5:1 ratios for 1st and reverse. That should help with this part of the test. It will be very interesting to see if the new 8- and 10-speed heavier-duty transmissions to be introduced soon have much lower initial gearing like their lighter counterparts.

I assume those are correct.

GM could NOT pass those tests so they have under 23k towing.

Watch GM magically hit 30k towing as soon as they release their new trans. I guarantee you it will have lower starting gears.