Truck Caps help when Towing??

[NNovak]

I did a search in the forum and only found some information on the wind deflectors for untop of the truck for fifth wheelers.



My question is when bumber hitch towing a 29ft Travel Trailer that is 11ft tall, would having a cab high truck cap help with wind push?



I would think the extra 2. 5ft would help specially over a soft tennue cover. but I wanted to ask before I go spend the $$ on a cap and find out it does the reverse and creates a drag.



I am open to a cap that is 4inches higher than the cab if that helps more.



I also notices many cap models have different angles for the back, some angle down earlier and some are more squared off. Do one of these styles better than the other?

 

[WestTN]

Attach a ribbon long enough to reach a couple of feet past the leading edge of the trailer roof and attach it to the trailing edge of the wing. The wing should be as far to the rear of the cap as possible. Have an observer watch the ribbon in relation to the roof and make adjustments as needed to the wing until the ribbon just rests lightly on top of the trailer. At that point you will be moving the air across the top of the trailer without wasting energy molving it too high. You may notice the angle of the wing is quite a bit different than you expected.

 

[MA2LA]

I tried one on my truck and din't see much of a diffrence, but the rear window of the cap was not there so that very well may have caused issuses

 

[GAmes]

Not only do you have to consider the height of the TT, but the width. Take a look at the profile of your pickup. It is wider in the middle than the grill or tailgate and the windows tilt in making the cab roof narrower than the hood. It is the same idea as the clone lozenge shaped sedans that have been produced for the last 10 or 12 years. By itself it is about as aerodynamic as you can make it. Do a little study about how air flows over and under a wing and you will see the same forces in motion. Forget adding a box that is taller and wider and trying to make the combo aerodynamic. Not only do you have all that surface area sticking above and to the sides of the truck, there is the under carriage as well. Don't forget that big flat suction cup on the back of the RV either. If you are buying a cap only to improve mileage it won't make enough difference to pay for itself until you log roughly the same amount of towing miles I have on mine (about 300k) and probably not then.

 

[AABEN]

Yes you can go to this site and check it out www.icontechltd.com---When i had a pull trailer i ran a ARE cap as tall as i could get. so i could hall my 4wheeler in it did a good job of moving the bugs to about a foot from the top of the camper. Had to have a spot where the tail gate set about level to load it in.

 

[GAmes]

These pictures are from the web site provided by blackbear.



It is amazing that their little arrows show the air flattening out after traveling over the windshield (which is what it really will do) but after moving over the deflector it magically keeps moving up, up and over the 5er. :-laf Also is a perfect example of the front profile. Notice the small surface area of the deflector being dwarfed by the frontal area of the 5er. Just that should be enough evidence that the huge gains in mpg that are reported are in fact just wishful thinking.

 

[Buffalo]

After towing for awhile, I have noticed the "Bug Line" on the front of the trailer. I think the ARE shell, I have, does help with the aerodynamics,a bit. Probably not worth buying the shell for its aerodynamic benefits, alone. However, having the bed of the truck protected & fairly secure has its benefits, also.



Joe F.

 

[AABEN]

The one I have is a lot like the WD400. My has gas shocks on it. It set up straight till moving down the road. It has a lot of adjustment to it also can be lade down flat. I am pulling a fifth wheel that is 38ft with a front living room witch is about a foot higher. I am getting about 2miles better on fuel. I will say that the short one would be waste of your money if you have a fifth wheel.

 

[NNovak]

Thanks for the info.

I am pulling a bumper hitch travel trailer. 11ft high.

Better Aero is just a side benny I was hopeing to get a bit of. Not for MPG purposes just to help the wind drag a bit.

I am going to get a Yakama rack set up for it, so maybe I can make a 'wing' to toss the air over it.