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Old 02-27-2013, 08:41 PM   #1
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SAE J-2807 New Towing Standard - Details

I hope this is not too much detail, but some out there may want to read this stuff…..zzzzzz

First, be aware that to get an actual copy of an SAE standard, requires purchasing the document from the SAE, Society of Automotive Engineers. We're talking maybe $200 or more. The info below is what I found in a publicly available document, and gives the highlights only.


Overview;

Five key areas are addressed by the SAE J-2807 standard
1. An engine’s power and torque characteristics
2. The powertrain’s cooling capacity
3. Chassis and powertrain durability
4. Handling during cornering and braking maneuvers
5. The vehicle’s hitch structure


Acceleration Requirements

The tow vehicle must meet this level of road performance while towing to claim a particular Tow Rating

Acceleration from zero to 30 mph;
1. in 12 seconds or less in a vehicle with single rear wheels
2. in 14 seconds or less in vehicles with dual rear wheels
3. in 16 seconds or less in vehicles with dual rear wheels and a GVWR over 13,000 lbs

Acceleration from zero to 60 mph;
1. in 30 seconds or less in vehicles with single rear wheels
2. in 35 seconds or less in vehicles with dual rear wheels
3. in 40 seconds or less in vehicles with dual rear wheels and a GVWR over 13,000 lbs

Forty to 60 mph passing acceleration;
1. in 18 seconds or less in vehicles with single rear wheels
2. in 21 seconds or less in vehicles with dual rear wheels
3. in 24 seconds or less in vehicles with dual rear wheels and a GVWR over 13,000 lbs


Grade Launch Requirements

The tow vehicle must be capable of repeatedly moving from rest for a distance of 16 feet on a 12 percent grade in both forward and reverse. Five such launches must be accomplished within 5 minutes in each direction.


Highway Grade Ability

To achieve a particular rating, a vehicle must maintain a minimum cruising speed while climbing the grade at Davis Dam on State Roads 68 and 163 in Arizona and Nevada. This 12 mile run originating in Bullhead City, Arizona, involves grades that vary from 3 to 7 percent with an average of more than 5 percent. During this test, the minimum acceptable ambient temperature is 100 degrees F. The AC system must be operating on the maximum cold setting with no recirculation, and the blower on the highest setting.

Single rear-wheel vehicles must be able to maintain an average of at least 40 mph on this grade. Dual rear-wheel vehicles are required to maintain 35 mph or more here. Dual rear-wheel vehicles with a GVWR over 13,000 lbs must maintain at least 30 mph.

To pass this test, there can be no vehicle component failures, no warning lamps, and no diagnostic codes alerting the driver. In addition, the tow vehicle cannot lose any engine coolant. The vehicle under test must be equipped with the lowest axle ratio available from the manufacturer.


Handling Requirements

The new standard specifies that an under-steering attitude must be maintained up to at least 0.4g cornering without a weight distributing hitch. With a weight distributing hitch, and under-steering attitude must be maintained up to only 0.3g cornering.


Braking Requirements

The test vehicle and trailer must stay within an 11.5 foot wide traffic lane during stopping tests. Stopping requirements from 20 mph without use of trailer brakes are;
1. in 35 feet or less with a tow rating of 3,000 lbs or less and no trailer brake requirement
2. in 45 feet or less with a tow rating of 3,000 lbs or less and a requirement for trailer brakes
3. in 80 feet or less for tow ratings above 3,000 lbs
The parking brake must be capable of holding the rig on 12 percent up and down grades


Hitch Structure

To assure the tow vehicle’s structure is capable of towing a particular trailer load, J2807 specifies that no more than 5 degrees of permanent angular deformation at the hitch attachment points is acceptable. Also, the highest trailer hitch attachment force experienced must be withstood for 5 seconds without significant loss deflection.

Finally, the SAE towing committee didn’t include items such as brake fade and/or durability issues in its standards, as these are already dealt with in other standards and each manufacturers own requirements.


My comment; It also doesn't seem to include lateral stability at highway speeds. But, since this info which I found is only an overview, maybe it's covered elsewhere?
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Old 02-27-2013, 10:35 PM   #2
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David,

Quote:
Originally Posted by David472 View Post
snip..... I hope this is not too much detail .....snip
Not at all..., and being familiar with SAE J2807 in a general sense may be helpful to the JOF reader because the topic sure has gone viral in the Tow Vehicle world.

Quote:
Originally Posted by David472 View Post
snip..... It also doesn't seem to include lateral stability at highway speeds. But, since this info which I found is only an overview, maybe it's covered elsewhere?
It's my understanding that one of the areas that the SAE J2807 tested was TV "Structure" which included the Body, Bumper, Frame Strength..., and the Hitch (as you mentioned). I don't know if "Frame Strength" testing was inclusive of the TV's suspension (ie, leaf springs, coils, etc.), and I don't recall if lateral stability was part of the Structure/Frame Strength testing.

Bob
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Old 02-28-2013, 02:45 AM   #3
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I was a little high on the cost to purchase this particular standard. From IHS Global, where I used to shop all the time for this kind of stuff, the cost is actually $75. Based on this price, I would say it's only a few pages long. So, if you want the real thing, go for it! Keep in mind, reading one standard may leave you wanting the other overlapping documents. You may need 4 or 5 feet of bookshelf to cover the range! These days, electronic pdf documents are all the rage for this type of thing.
http://global.ihs.com/
Search here for SAE J2807
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Old 02-28-2013, 05:20 AM   #4
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David472,

Thanks for the overview - never too much detail for me. (I think there are two groups out here: those that like a lot of detail; and those that don't want any.) I said in the other current WD thread that the cost of the document was too expensive for me. We have to accept many technical issues (almost all products) are resolved by design engineers before we use them. That will probably be the case for me on this one. I'm sure Rustic Eagle will involve himself much more. So, I'll be watching to see how it turns out as an industry standard.

I hope when "they're" finished we can still afford to tow. Over-doing-it seems to be a trend in problem resolution across the board. So, I'm going to check my old tent for holes just in case.

On the lighter side: I can imagine future TV's coming equipped with a FALR meter built into the front fender.
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Old 02-28-2013, 09:46 AM   #5
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OnTheGo;

Yes, it can get quite expensive to obtain a bunch of these standards. It was the company(s) I worked for who purchased the ones I used in my job. Even then, the people who controlled the dollars would sometimes give me grief about the cost. I had a habit of only obtaining a couple at a time to keep them happy.

Your idea of a FALR meter is interesting. We joke about it now, but who knows? It wasn't that long ago that tire pressure monitoring while in motion was a far-fetched idea. Now TPMS is well established. You're right about this type of thing driving up costs. We all get dragged kicking and screaming into the future!
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