RV wind deflectors????????

[zell66]

Looking a purchasing a wind deflector to place on top of my 08 f-350. In doing research I have seen many pros and cons to doing this. I would like members with REAL WORLD experiences tell me about before and after use. Was MPG improved? If so by how much? Also wind noise tolerable or not?

Thanks

[GordonThree]

Something on the rear of the trailer will help more than anything in the front.

Need more mpg? Foot off the gas is the most effective solution.

[Old-Biscuit]

According to profile OP has a 5TH WHEEL....HIGH PROFILE

No bed topper...no low profile TT

9000# F350 4x4
13,000# FW

[fj12ryder]

zell66 wrote:

Desert Captain wrote:
Since I sold my TT and truck 5 years ago I no longer have dog in this fight but:
{Currently have a 24' Class C and usually tow a 10' cargo trailer for my Indian Springfield.}

The OP asked and actually having had first hand, real world experience I shared {see my earlier post complete with a pic of the rig}. Unless you have some, "Frankly Scarlet"...

Set one up correctly at the rear of the truck, experiment until you find the optimum angle of attack and they work. It is just that simple. I never thought 1.5 - 2 mpg was anything to write home about but over the first year it paid for the deflector. After that it was a savings in fuel costs, not a lot, but free.

:S

That is my thinking. I can buy a used one for $120 and the first trip we have planned if I get 1 to 2mpg better it will pay for it. But very little positive vibes for them.

You're not going to see any savings unless you set it up at the rear of the truck on a bed topper, and have a fairly low trailer. The only reason it worked in this application was it was very close to the trailer. Mounted on the top of the truck cab will be pretty much useless. And it will do nothing with a 5th wheel.

[zell66]

Desert Captain wrote:
Since I sold my TT and truck 5 years ago I no longer have dog in this fight but:
{Currently have a 24' Class C and usually tow a 10' cargo trailer for my Indian Springfield.}

The OP asked and actually having had first hand, real world experience I shared {see my earlier post complete with a pic of the rig}. Unless you have some, "Frankly Scarlet"...

Set one up correctly at the rear of the truck, experiment until you find the optimum angle of attack and they work. It is just that simple. I never thought 1.5 - 2 mpg was anything to write home about but over the first year it paid for the deflector. After that it was a savings in fuel costs, not a lot, but free.

:S

That is my thinking. I can buy a used one for $120 and the first trip we have planned if I get 1 to 2mpg better it will pay for it. But very little positive vibes for them.

[Desert_Captain]

Since I sold my TT and truck 5 years ago I no longer have dog in this fight but:
{Currently have a 24' Class C and usually tow a 10' cargo trailer for my Indian Springfield.}

The OP asked and actually having had first hand, real world experience I shared {see my earlier post complete with a pic of the rig}. Unless you have some, "Frankly Scarlet"...

Set one up correctly at the rear of the truck, experiment until you find the optimum angle of attack and they work. It is just that simple. I never thought 1.5 - 2 mpg was anything to write home about but over the first year it paid for the deflector. After that it was a savings in fuel costs, not a lot, but free.

:S

[Lwiddis]

Used to see them all the time on TVs pulling 5ers and TTs. Rare now.

[IdaD]

I think there’s something to wind deflectors in theory or you wouldn’t see commercial trucks with them where the bottom line is dollars. I don’t think they have any practical application to a pickup pulling a camper trailer, though.

[Cummins12V98]

I love people that have these and they drive around BobTail with the wing up.

[Old-Biscuit]

9000# F350 4x4 towing 13,000 5th wheel.
Air deflector on cab of truck improve your mileage......NOPE


Towing at 62 mph would make better MPH then air deflector
And if already towing at that speed then you might want to have engine diagnostic done (8 mpg/diesel IS low....if GAS---then it is what it is)

[Turtle_n_Peeps]

carringb wrote:
On pickups, the cab-to-trailer gap is generally too large for a wind deflector to realize any benefit. It may even make aero worse, since the air coming off the wing will likely crash into the front of the trailer, rather that going over it. But then you now have another low-pressure zone behind the wing adding drag.

Minimizing the cab-trailer gap, and cleaning up the air coming off the back of the trailer are probably the two easiest things to do. After that, you have to look at minimizing the air going under the front of the truck (which is why the Freightliner New Cascadia is only a few inches off the pavement), then keep it from getting sucked under the sides.

I have never ran a wing on my truck nor will I ever. I have raced cars for over 40 years and have learned somethings about aero over the years.

The things I have learned over the years about aero are pretty much condensed into what Bryan has typed.

The two big problems are air getting under the truck and trailer and the air trying to get in back of the wing just as Bryan has said. One more big deal is the air trying to suck the trailer backwards after it passes the back of the trailer. IOW's the back of the trailer is every bit as important as the front of the trailer.

A really smart guy a very long time ago by the name of Aristotle once said: "Nature abhors a vacuum." He was absolutely correct. Air is very sneaky! If you keep it from out under your truck, it wants to sneak back in. Hence the reason for side skirts on race cars.

One thing that does work (ever so slightly) is air tabs. They help by taking some of the vacuum away from the back of the trailer. Unless you full time many, many, many miles a year you will never get your money back on any of this stuff.

If I had to sum it up about wings on a pickup truck pulling a TT it's like putting lipstick on a pig. To some people the pig looks pretty with a nice shade of lipstick on. But to people in the know, they just look at the pig and say, "it's still just a pig wearing lipstick."

[Tyler0215]

1.5 to 2 mpg improvement? That's hard to believe.

[N-Trouble]

Looks aside, not sure what these things go for but you have to figure out realistically how many miles would you have to drive to hit a break even point?

[DownTheAvenue]

carringb wrote:
On pickups, the cab-to-trailer gap is generally too large for a wind deflector to realize any benefit. It may even make aero worse, since the air coming off the wing will likely crash into the front of the trailer, rather that going over it. But then you now have another low-pressure zone behind the wing adding drag.

This is exactly correct.

Also think about the additional wind resistance that deflector will cause when you drive round without the trailer attached.

Safe your money; don't buy snake oil.

[Desert_Captain]

They are not "snake oil", properly set up they will improve your mileage. I ran one, can't remember the brand, for 3.5 years mounted on the rear of my Leer Shell on an F-150 SCab towing a 22' 5,600# TT. It worked very well gaining me 1.5 to 2 additional mpg. This paid the $350 purchase price back in a year.

As noted I believe the key to my success was the fact that it was mounted at the rear of the truck, closing the gap with the front of the trailer. It only took a couple of minutes to mount and was very secure with no additional wind noise. Of course, I only ran it when towing.

We logged about 15,000 miles a year with this setup and I never had a negative experience and the mileage improvement was amazingly consistent {I always ran with my Scan Guage documenting/supplementing my pump calculations.}

Here is a shot taken at Quartzsite 8 years ago:

Moderator edit to re-size picture to forum recommended limit of 640px maximum width.

:C

[carringb]

On pickups, the cab-to-trailer gap is generally too large for a wind deflector to realize any benefit. It may even make aero worse, since the air coming off the wing will likely crash into the front of the trailer, rather that going over it. But then you now have another low-pressure zone behind the wing adding drag.

Minimizing the cab-trailer gap, and cleaning up the air coming off the back of the trailer are probably the two easiest things to do. After that, you have to look at minimizing the air going under the front of the truck (which is why the Freightliner New Cascadia is only a few inches off the pavement), then keep it from getting sucked under the sides.