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Wind Deflector/Wing: MPG Gain?
- Thread starter hhranch
- Start Date
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Of all the people I have talked to just about all have said little or no difference. Now there are 2 good things I know of, they keep the bugs off the 5er and the cool factor of the polished wing on the roof :-laf .
I have one from Taylor. I have had it on three trucks now. I gained about 10% or better like they claim. It makes the trailer more steady as well. Look at the over the road trucks, most of them have some sort of chicken slide on them. They are there for a reason, They help. A person would have to pull a lot to verify the expense but possibly except for the air ride hitch and jake brake it rates at the top of towing helpers in my book!
just realize it's going to hurt mpg empty
These deflectors have very little effect on fuel economy. If you look at the fairings for big rigs you'll note that they tend to be very close to the trailer. I don't fully understand the aerodynamics, but apparently if there is very much gap between the fairing and the trailer the wind tends to spill into the area between the fairing and trailer causing drag.
They will help some with the bugs, but for the expense I'll just wash 'em off.
They will help some with the bugs, but for the expense I'll just wash 'em off.
What type of hitch do you have for the Titanium using a short bed truck?? It doesn't appear that you have an extended pin box. Do you have a sliding hitch for tight turns?? If you have photos of your hitch, I would like to see them.
Thanks, Chuck
________________________________________________________________________
2006 Laramie 3500 QC SB 4x4
2001 Cardinal 28ft Fiver w/2 slides Rr kitchen
Thanks, Chuck
________________________________________________________________________
2006 Laramie 3500 QC SB 4x4
2001 Cardinal 28ft Fiver w/2 slides Rr kitchen
You will have no increase in milage with the wing. I've been towing with mine for 4 years, and the only thing I've been able to see as an asset, is the deflector has nurmerous crack and chips from objects coming from the road. I had rather replace the deflector than the front cap. And it does help with bugs
. . Preston. .
. . Preston. .
A step in the right direction, but 15-30% fuel savings is B. S. .
The best results would be achieved with something like a one piece design that extended further back on the sides and top with the deflector smoothly faired.
Big rig designers can optimize design because the design of most freight vans are very similar and they are producing thousand of the same trucks to mate up with these trailers with a common design. Even with the ability to optimize the design, I think fuel savings were 10-15% at typical highway speeds.
I agree that the best use of most of these deflectors is bug/debris control, not fuel savings.
The best results would be achieved with something like a one piece design that extended further back on the sides and top with the deflector smoothly faired.
Big rig designers can optimize design because the design of most freight vans are very similar and they are producing thousand of the same trucks to mate up with these trailers with a common design. Even with the ability to optimize the design, I think fuel savings were 10-15% at typical highway speeds.
I agree that the best use of most of these deflectors is bug/debris control, not fuel savings.
JWChessell
TDR MEMBER
A few days ago I posted this on the 3rd Gen "No Engine/Trans" forum, and thought it might be of interest here.
Since Feb '06 I've been hauling a 16' dbl-axle cargo trailer back/forth from so. Calif. to NW Washington and return, almost all of it on I-5; same route almost every time, same fuel stops almost every time, same tire pressure, and almost same speeds each time on each leg. I've keep a detailed log of these trips with approx 30 separate pieces of information for each leg. I've weighed the trailer several times, and wind-resistance appears to make more difference in mileage than weight; also wind resistance increases geometrically as speed increases. Trailer weight has ranged from a low of 2,840 lbs to a high of 7,020 lbs.
Between 2-19-06 and 5-5-06 I drove 5,144 miles on this route with NO wind deflector, except my cab-height shell. Between 7-1-06 and 12-5-06 I drove 11,123 miles on this route, using a Trail-Eze wind-deflector (made by Ultra-Fab) that I purchased in a salvage yard and mounted on my shell (Ultra-Fab mounts these exclusively on a headache rack and advised me NOT to mount one on my shell; in retrospect they were either overly cautious, or "no" was the easy answer). See the attached photo of the rig with the deflector set to approx 40 degrees (it will also fold flat when not in use, and although difficult, I can mount it or remove it without help). Sorry about the photo being vertical; the forum computer will allow 500 X 800 px, but not 800 X 500. Go figure.
The difference in mileage by using the deflector, calculated over 11,123 miles, is an increase of between 1 and 1. 5 MPG. Without the deflector, the average mileage while towing was 11. 895 MPG. With the deflector, the average mileage has been 12. 941 MPG. That is an average increase of just slightly over 9%.
It's hard to be more definitive, because there are a LOT of variables. Speed and terrain are the most important; rain increases rolling resistance; wind has an effect if opposing, following or quartering; weight does have some effect. The deflector angle makes a significant difference -- I experimented, using deflector angles between 55 and 35 degrees on each leg of the route, both north-bound and south-bound -- the best angles are either 35 or 40 degrees. Heavy vs. light traffic has an influence; tire pressure makes a difference. I started out towing at about 66 MPH, and have gradually reduced that to an overall 61 MPH -- in part because the mileage is more consistent, and in part because my speed is more constant and I can interact more efficiently with heavy trucks.
During the course of using the deflector, I have seen many varying deflectors on pickup trucks towing trailers; I spoken with three Dodge owners regarding their deflectors. One was similar to the photo posted by Andler, but smaller. It fastened to the top of the Quad-Cab with nylon straps which were anchored inside the rear doors. The owner had purchased it on the internet from Canada and the price was about $250. 00 U. S. The second Dodge owner had a Trail-Eze mounted on a headache rack, and no shell (cost of these is around $500, more or less). The third had a curved stainless-steel foil (looks like an airplane wing upside-down) mounted on a headache rack (cost unknown). Each of the owners was towing either a travel trailer or a 5th-wheel trailer, and each said the same thing: They had obtained an increase in mileage of between 1 and 1. 5 MPG depending on circumstances.
I purchased my deflector in a salvage yard for $75. 00 and made the fully-adjustable mount myself. Total cost was approximately $325. 00 -- and I'm unaware of any mounting system available commercially to mount the deflector on top of a shell. Contrary to Trail-Eze' concerns about mounting the deflector in such a manner, I have experienced NO side-effects from the mount, and I've logged this information also. In 11,123 miles of towing with the deflector raised, I can find NO damage to the shell, nor has the shell moved even a fraction of an inch on the bed of the truck. Also, my calculations indicate that I am just now at about the "break-even" point concerning the cost of the deflector and installation vs. the savings in fuel.
The next experiment is to move the deflector farther aft on the shell, so it's closer to the trailer.
IMO, and in those of others I have read on this forum and the towing forum, claims of mileage increases over 15% are exaggerated; between 8 and 12 % would be more realistic.
Since Feb '06 I've been hauling a 16' dbl-axle cargo trailer back/forth from so. Calif. to NW Washington and return, almost all of it on I-5; same route almost every time, same fuel stops almost every time, same tire pressure, and almost same speeds each time on each leg. I've keep a detailed log of these trips with approx 30 separate pieces of information for each leg. I've weighed the trailer several times, and wind-resistance appears to make more difference in mileage than weight; also wind resistance increases geometrically as speed increases. Trailer weight has ranged from a low of 2,840 lbs to a high of 7,020 lbs.
Between 2-19-06 and 5-5-06 I drove 5,144 miles on this route with NO wind deflector, except my cab-height shell. Between 7-1-06 and 12-5-06 I drove 11,123 miles on this route, using a Trail-Eze wind-deflector (made by Ultra-Fab) that I purchased in a salvage yard and mounted on my shell (Ultra-Fab mounts these exclusively on a headache rack and advised me NOT to mount one on my shell; in retrospect they were either overly cautious, or "no" was the easy answer). See the attached photo of the rig with the deflector set to approx 40 degrees (it will also fold flat when not in use, and although difficult, I can mount it or remove it without help). Sorry about the photo being vertical; the forum computer will allow 500 X 800 px, but not 800 X 500. Go figure.
The difference in mileage by using the deflector, calculated over 11,123 miles, is an increase of between 1 and 1. 5 MPG. Without the deflector, the average mileage while towing was 11. 895 MPG. With the deflector, the average mileage has been 12. 941 MPG. That is an average increase of just slightly over 9%.
It's hard to be more definitive, because there are a LOT of variables. Speed and terrain are the most important; rain increases rolling resistance; wind has an effect if opposing, following or quartering; weight does have some effect. The deflector angle makes a significant difference -- I experimented, using deflector angles between 55 and 35 degrees on each leg of the route, both north-bound and south-bound -- the best angles are either 35 or 40 degrees. Heavy vs. light traffic has an influence; tire pressure makes a difference. I started out towing at about 66 MPH, and have gradually reduced that to an overall 61 MPH -- in part because the mileage is more consistent, and in part because my speed is more constant and I can interact more efficiently with heavy trucks.
During the course of using the deflector, I have seen many varying deflectors on pickup trucks towing trailers; I spoken with three Dodge owners regarding their deflectors. One was similar to the photo posted by Andler, but smaller. It fastened to the top of the Quad-Cab with nylon straps which were anchored inside the rear doors. The owner had purchased it on the internet from Canada and the price was about $250. 00 U. S. The second Dodge owner had a Trail-Eze mounted on a headache rack, and no shell (cost of these is around $500, more or less). The third had a curved stainless-steel foil (looks like an airplane wing upside-down) mounted on a headache rack (cost unknown). Each of the owners was towing either a travel trailer or a 5th-wheel trailer, and each said the same thing: They had obtained an increase in mileage of between 1 and 1. 5 MPG depending on circumstances.
I purchased my deflector in a salvage yard for $75. 00 and made the fully-adjustable mount myself. Total cost was approximately $325. 00 -- and I'm unaware of any mounting system available commercially to mount the deflector on top of a shell. Contrary to Trail-Eze' concerns about mounting the deflector in such a manner, I have experienced NO side-effects from the mount, and I've logged this information also. In 11,123 miles of towing with the deflector raised, I can find NO damage to the shell, nor has the shell moved even a fraction of an inch on the bed of the truck. Also, my calculations indicate that I am just now at about the "break-even" point concerning the cost of the deflector and installation vs. the savings in fuel.
The next experiment is to move the deflector farther aft on the shell, so it's closer to the trailer.
IMO, and in those of others I have read on this forum and the towing forum, claims of mileage increases over 15% are exaggerated; between 8 and 12 % would be more realistic.
How did you factor this into your calculations? I've found that a reduction in speed from 70 MPH to 62 MPH with our 16K GVWR, 13'2" tall 5th wheel increases mileage from 9. 5 MPG to 10. 5-11. 0 MPG, or an increase of 10. 5% to 15. 8%, which is as much or more than the mileage improvement you attribute to the wind deflector.JWChessell said:
Rusty
JWChessell
TDR MEMBER
When I read RustyJC's reply on Dec. 14th, I was a little annoyed. After all, I'd spent the money, done the work, driven the miles, kept the logs, and was sure that the wind deflector was saving me money, even if only a small amount. So, I decided to prove, at least to myself, that RustyJC was wrong. On Dec. 23rd I began another round trip from so. Calif to nw Wash via I-5. I did not raise the deflector, kept the speed to 61 MPH and fueled at all the same locations. Everything was as usual, except the deflector was down, not up. I expected that the mileage would be lower.
Well, RustyJC was not wrong, and was probably right; the mileage was exactly the same! So, I kept the deflector down for the return south-bound trip. Again, mileage was exactly the same as the previous south-bound trip when the deflector had been raised to 40 degrees.
I made another round trip at the end of January, this time with the deflector up. Same result; MPG figures were the same as with the deflector down. On March 16th I made another trip north, this time with the deflector up and a steady speed of 64 to 65 MPH. The mileage figures were the same as they had been in February 2006, when I drove the same speeds while towing the same trailer without a deflector.
Between 2-19-06 and 3-20-07 I towed the same trailer, both loaded and empty, a total of 23,414 miles north and south on I-5 between nw Wash and so. Calif. 5,144 miles were with no deflector; 2,296 miles were with the deflector down (a total of 7,740 miles). 15,674 miles were with the deflector up, at angles of between 55 degrees and 35 degrees, but most commonly at 40 degrees. I tried to keep the same speeds over the same stretches of road, fueled at the same places on each trip, weighed the trailer on the north-bound trips, and kept an accurate log with about 15 separate pcs of information. All I can say after that time and mileage is there is not a measurable difference in fuel consumption/savings that can be attributed to the wind deflector.
There MAY be a fuel savings, but the amount is so small it is in the same range as all the other variables -- road surface, terrain, tire pressure, rolling resistance, wind speed and angle, rain, trailer weight, quality of fuel, etc. -- and cannot be measured without much more sophisticated equipment, such as a wind-tunnel. As has been mentioned, there are NO bugs on the front of the trailer when the deflector is raised, so it obviously has SOME effect on the air passing over the trailer. However, whether it lifts the air over the trailer or merely disturbs it so the bugs don't impact and stick is unknown.
IF the wind deflector actually improves mileage as much as 1/2 MPG -- and I have no information to show that it does -- at 12 MPG with fuel at $2. 85/gal I would have to tow the trailer about 33,000 miles to recover my cost of approx $325. 00 to install the deflector; at the same MPG and fuel cost those spending $500 to have a deflector installed professionally would have to tow approx 52,000 miles to recover their costs of installation. If it is only saving 1/4 MPG at an average 12 MPG, those towing distances -- before the cost of installation is amortized -- are doubled.
Having spent the money, built the deflector and installed it, I'll continue to use it when I tow the trailer, based on the possibility that it is saving me SOMETHING; and, it does not appear to be costing me anything (other than the original costs of construction and installation). However, having driven the miles and having kept the figures, in hindsight I would not spend the money to install one; in my opinion the savings -- IF ANY -- are not recoverable in any reasonable period of time.
RustyJC -- YOU WERE RIGHT.
Well, RustyJC was not wrong, and was probably right; the mileage was exactly the same! So, I kept the deflector down for the return south-bound trip. Again, mileage was exactly the same as the previous south-bound trip when the deflector had been raised to 40 degrees.
I made another round trip at the end of January, this time with the deflector up. Same result; MPG figures were the same as with the deflector down. On March 16th I made another trip north, this time with the deflector up and a steady speed of 64 to 65 MPH. The mileage figures were the same as they had been in February 2006, when I drove the same speeds while towing the same trailer without a deflector.
Between 2-19-06 and 3-20-07 I towed the same trailer, both loaded and empty, a total of 23,414 miles north and south on I-5 between nw Wash and so. Calif. 5,144 miles were with no deflector; 2,296 miles were with the deflector down (a total of 7,740 miles). 15,674 miles were with the deflector up, at angles of between 55 degrees and 35 degrees, but most commonly at 40 degrees. I tried to keep the same speeds over the same stretches of road, fueled at the same places on each trip, weighed the trailer on the north-bound trips, and kept an accurate log with about 15 separate pcs of information. All I can say after that time and mileage is there is not a measurable difference in fuel consumption/savings that can be attributed to the wind deflector.
There MAY be a fuel savings, but the amount is so small it is in the same range as all the other variables -- road surface, terrain, tire pressure, rolling resistance, wind speed and angle, rain, trailer weight, quality of fuel, etc. -- and cannot be measured without much more sophisticated equipment, such as a wind-tunnel. As has been mentioned, there are NO bugs on the front of the trailer when the deflector is raised, so it obviously has SOME effect on the air passing over the trailer. However, whether it lifts the air over the trailer or merely disturbs it so the bugs don't impact and stick is unknown.
IF the wind deflector actually improves mileage as much as 1/2 MPG -- and I have no information to show that it does -- at 12 MPG with fuel at $2. 85/gal I would have to tow the trailer about 33,000 miles to recover my cost of approx $325. 00 to install the deflector; at the same MPG and fuel cost those spending $500 to have a deflector installed professionally would have to tow approx 52,000 miles to recover their costs of installation. If it is only saving 1/4 MPG at an average 12 MPG, those towing distances -- before the cost of installation is amortized -- are doubled.
Having spent the money, built the deflector and installed it, I'll continue to use it when I tow the trailer, based on the possibility that it is saving me SOMETHING; and, it does not appear to be costing me anything (other than the original costs of construction and installation). However, having driven the miles and having kept the figures, in hindsight I would not spend the money to install one; in my opinion the savings -- IF ANY -- are not recoverable in any reasonable period of time.
RustyJC -- YOU WERE RIGHT.
Thanks, JW. I, for one, appreciate your willingness to share your documented experience. The numbers tell the tale.
Rusty
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Issue 128 – Digital Version
Digital Magazines
FREE!
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Renew
Subscribe
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Back Issues
Subscription Status
Address Change Form
Buyer's Guides
Ram Diagnostic Trouble Codes
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