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Old 12-21-2014, 01:50 AM   #61
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Originally Posted by Jfocallag View Post
Hi, I want to make sure that I understand the frontal area issue. The frontal area for a 15 foot escape is 43.5 sqft based on the H X W X .8: 8.16 X 6.66 x.8 = 43.5. I assume the .8 is for ground clearance. I found this formula on the web.

The manual for the Nissan Frontier says that the maximum frontal area should be 30 sqft.
Where on the web? Anyone can post anything...

Multiplying the area by a reduction factor makes no sense to me as a way to account for ground clearance. One source suggests
Quote:
typically defined as width x (height - .75) in sq. ft.
which means subtract 0.75' (9") from the height, I guess because he has 9" of ground clearance... that makes more sense. Doing the same thing with a width of 6.66' and a height of 8.16' would be
6.66' x (8.16-0.75)' = 49.35 ft2
If the 0.8 factor is applied to the whole area, that sounds more like a high coefficient of drag (Cd = 0.80) applied to calculate CdA... but that's not what the tug manufacturer says is the area limit applies to.

Maybe the most likely is that it is allowing for rounded corners, as viewed in silhouette from the front... in that case, accuracy is just a matter of determining the correct factor.
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Old 12-21-2014, 09:02 AM   #62
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Basically the frontal area for a 15' Escape is between 43 and 55 sqft depending upon how you measure it. The maximum frontal area for the 2014 Nissan Frontier is 30. Used to be 60 based on 2013 manual. They have adopted the J2807 standard. Did they have to decrease the frontal area maximum in order to keep the rest of the ratings the same? Just conjecture. Only way to know would be to contact an engineer at Nissan.
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Old 12-21-2014, 10:09 AM   #63
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I think frontal area maximums are recommendations, and rather silly ones at that. I called a friend who works for Ford and he gave me an example. His F150 has a max frontal area listing of 60. The total area that both the TV and the trailer expose to wind resistance should not be more than 60 sq feet according to this. The truck makes up some of that, and the trailer (the portion the TV doesn't block at least) makes up the rest. If you were to take that literally, they'd be saying you should only tow tiny trailers with an F150 - which is patently false.

The other thing is that Ford (and I'm assuming other manufacturers as well) won't try to void your TV warranty because you exceeded their maximum frontal area numbers. From all of this, I conclude its a number that is not worth worrying about.
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Old 12-21-2014, 10:16 AM   #64
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Originally Posted by Jfocallag View Post
Basically the frontal area for a 15' Escape is between 43 and 55 sqft depending upon how you measure it. The maximum frontal area for the 2014 Nissan Frontier is 30. Used to be 60 based on 2013 manual. They have adopted the J2807 standard. Did they have to decrease the frontal area maximum in order to keep the rest of the ratings the same? Just conjecture. Only way to know would be to contact an engineer at Nissan.
The other surprise in the Nissan Frontier manual is "Nissan recommends the use of a tandem axle trailer whenever towing above 3,000 lb.". It is easy for a 15 to be over 3,000 if it is a B and a 17 definitely is and both single axle. The 12 pages of towing requirements , especially the MAXIMUM trailer frontal area of 30 sq ft, seems to contrast with Nissan's prolific ads touting the 6,100-6,300 pound tow capacity. Nissan also reminds us in the manual that the Frontier is primarily a passenger vehicle that may be used for occasional towing. Hmmm... And we JUST bought a Frontier as our new tow vehicle. Wish someone had started this frontal discussion 2 weeks ago. Still, there are a large number of folks towing more with their Frontiers AND we have towed over 19,000 miles with our Santa Fe so the Frontier has got to be AS good if not better, so guess we will just have to find out.
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Old 12-21-2014, 10:17 AM   #65
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Did you click on 17B tab on post number 5 and read Gabe's story? To me this frontal area spec is an inconvenient truth for many out there.

For the Nissan Frontier, not sure what trans they are using now however the Pathfinder went to a CVT recently, and coincidentally when speaking with Gabe he relayed that a friend of his blew a CVT trans on their new Pathfinder and Nissan was a bear to deal with.
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Old 12-21-2014, 10:53 AM   #66
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Out of interest I looked for my 2008 Tacoma, the manual makes not mention any frontal area spec. In a quick Google search I couldn't find any references in anything official from Toyota about towing and any frontal area specs.
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Old 12-21-2014, 10:53 AM   #67
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Say, does Alf only count the area above the cab on his frontal calculations? How does that work for a 5th wheel?
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Old 12-21-2014, 11:00 AM   #68
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There are other frontal areas... (you got an app for that?)
Attached Thumbnails
frontalarea2.jpg  
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Old 12-21-2014, 11:07 AM   #69
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Did you click on 17B tab on post number 5 and read Gabe's story? To me this frontal area spec is an inconvenient truth for many out there.
That is an anecdote, not evidence.
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Old 12-21-2014, 11:11 AM   #70
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The other surprise in the Nissan Frontier manual is "Nissan recommends the use of a tandem axle trailer whenever towing above 3,000 lb.". It is easy for a 15 to be over 3,000 if it is a B and a 17 definitely is and both single axle. The 12 pages of towing requirements , especially the MAXIMUM trailer frontal area of 30 sq ft, seems to contrast with Nissan's prolific ads touting the 6,100-6,300 pound tow capacity. Nissan also reminds us in the manual that the Frontier is primarily a passenger vehicle that may be used for occasional towing. Hmmm... And we JUST bought a Frontier as our new tow vehicle. Wish someone had started this frontal discussion 2 weeks ago. Still, there are a large number of folks towing more with their Frontiers AND we have towed over 19,000 miles with our Santa Fe so the Frontier has got to be AS good if not better, so guess we will just have to find out.
If you just bought a Frontier as your TV, I'd say 'congratulations on your purchase' and leave it at that. While I always appreciate the technical info, honestly I think some threads get people worked up about things that don't really matter - and 'maximum frontal area' is one of those. The specs I worry about are GVWR, tongue weight and towing capacity. Have a cushion and you'll be FINE, IMHO.
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Old 12-21-2014, 11:17 AM   #71
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Originally Posted by rbryan4 View Post
If you just bought a Frontier as your TV, I'd say 'congratulations on your purchase' and leave it at that. While I always appreciate the technical info, honestly I think some threads get people worked up about things that don't really matter - and 'maximum frontal area' is one of those. The specs I worry about are GVWR, tongue weight and towing capacity. Have a cushion and you'll be FINE, IMHO.
and

I often wonder how many things in the manuals are written by actual engineers and how many by corporate lawyers....
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Old 12-21-2014, 11:23 AM   #72
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Can't blame it all on the lawyers.
We also have a penchant for taking recommendations as regulations, writ in stone. The word "may" becomes "must".
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Old 12-21-2014, 11:45 AM   #73
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Originally Posted by rbryan4 View Post
If you just bought a Frontier as your TV, I'd say 'congratulations on your purchase' and leave it at that. While I always appreciate the technical info, honestly I think some threads get people worked up about things that don't really matter - and 'maximum frontal area' is one of those. The specs I worry about are GVWR, tongue weight and towing capacity. Have a cushion and you'll be FINE, IMHO.
At last, a voice of reason from the wilderness! As stated earlier, until somebody gets access to a wind tunnel and a team of engineers, the only thing gained by the OP is a bunch of well-intentioned opinions from a group of nice folks. And, probably a considerable amount of anxiety.

For what it's worth OP, my extremely amateur experience shows me that my Frontier pulls my 19' like a champ.
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Old 12-21-2014, 12:25 PM   #74
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Originally Posted by Jfocallag View Post
Basically the frontal area for a 15' Escape is between 43 and 55 sqft depending upon how you measure it. The maximum frontal area for the 2014 Nissan Frontier is 30. Used to be 60 based on 2013 manual. They have adopted the J2807 standard. Did they have to decrease the frontal area maximum in order to keep the rest of the ratings the same? Just conjecture. Only way to know would be to contact an engineer at Nissan.
I agree that we're only speculating, and my guess is the same: perhaps in the J2807 test, the Frontier did fine with the previously rated trailer weight in grade climbing and acceleration, but ran too hot in sustained higher-speed sections with too much aero drag, so they knocked the frontal area down.

Of course, no engineer for Nissan (or any other manufacturer) will be free to answer this type of question.
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Old 12-21-2014, 12:27 PM   #75
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The other surprise in the Nissan Frontier manual is "Nissan recommends the use of a tandem axle trailer whenever towing above 3,000 lb.". It is easy for a 15 to be over 3,000 if it is a B and a 17 definitely is and both single axle. The 12 pages of towing requirements , especially the MAXIMUM trailer frontal area of 30 sq ft, seems to contrast with Nissan's prolific ads touting the 6,100-6,300 pound tow capacity.
I think this is a good example of recommendations which are well-intentioned (tandem axles generally increase stability) but are unreasonable if applied as an absolute rule. The classic Toyota equivalent says that the maximum speed for towing of any trailer is something like 45 mph (72 km/h) - that's fine if you're pushing your luck with the worst possible trailer otherwise fitting the limits, but it's ridiculous as a limit.

To be fair to Nissan, most trailers over 3000 pounds - and almost all trailers at 6000 pounds - have tandem axles, so this recommendation doesn't prevent a typical owner from reaching the rated limit even if they choose to follow it. Combined with the frontal area limit, viable trailers would typically be flat-deck cargo and auto carriers, which are pretty common pickup truck loads; it does suggest that three-ton travel trailers are not likely within the limits, but is that what Nissan shows in ads?
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Old 12-21-2014, 12:28 PM   #76
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For the Nissan Frontier, not sure what trans they are using now however the Pathfinder went to a CVT recently, and coincidentally when speaking with Gabe he relayed that a friend of his blew a CVT trans on their new Pathfinder and Nissan was a bear to deal with.
The Frontier transmission is certainly not a CVT. The challenge with current CVT designs is that they are friction drives, so they use a very specific lubricant which helps shafts rotate with less friction, but turns grippy under the high pressure between the drive surfaces. This creates a combination of high heat generation (if there is the slightest slippage at all) and temperature sensitivity (due to the fluid characteristics) so it is hard to prepare a CVT for heavy-duty use.

The Frontier, on the other hand, has a conventional gear transmission, chosen to handle the engine power and used worldwide to work harder than towing an Escape requires.
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Old 12-21-2014, 12:29 PM   #77
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Out of interest I looked for my 2008 Tacoma, the manual makes not mention any frontal area spec. In a quick Google search I couldn't find any references in anything official from Toyota about towing and any frontal area specs.
I've read towing sections of owners' manuals for several Toyota models, as well as the towing guide, and I've never seen an area limit, either. Maybe at 72 km/h aero doesn't matter...
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Old 12-21-2014, 12:31 PM   #78
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Can't blame it all on the lawyers.
We also have a penchant for taking recommendations as regulations, writ in stone. The word "may" becomes "must".
Spot on. Also, Escape owners are a pretty discriminating bunch -- that's why we chose escape over a sticky or some other brand. That can sometimes make them sweat details that others simply don't consider. Good in some ways, not so good in others.
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Old 12-21-2014, 12:33 PM   #79
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Say, does Alf only count the area above the cab on his frontal calculations? How does that work for a 5th wheel?
I don't see why a fifth-wheel is any different. Stand in front of the rig (preferably far away for perspective), and the area of the silhouette you see is the frontal area.

Whether the top of the trailer is behind the truck or right on top of it will change the drag, but this area limit is a gross approximation to aerodynamic drag load and doesn't consider any other aspect of the configuration, so why would this be considered?
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Old 12-21-2014, 12:36 PM   #80
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As stated earlier, until somebody gets access to a wind tunnel and a team of engineers, the only thing gained by the OP is a bunch of well-intentioned opinions from a group of nice folks. And, probably a considerable amount of anxiety.
I take a different view: there's also a better understanding of the factors involved in the load added by towing.

It is certainly possible to evaluate air drag without a wind tunnel - using a coast-down method - but I haven't gotten around to doing that, and I don't think any manufacturer is going to suggest in the manual that any owner do it, either.
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