I doubt that I'll ever overhear this in a diner on the highway...

"Hey George, how's the long drive?"

"Well, it's been dandy, Bill. I had this beautiful Ford Escape Hybrid stuck to my rear bumper bumming a free ride for the last 200 miles. It was real fun because he saved a ton of fuel in my draft and it only cost me $5.00 extra in gas! I love having cars on my butt so much I just bought extra long mud flaps so I don't chip their beautiful paint".

 

Walt and Roch... this is so UNTRUE I don't even know where to begin.
It is unsafe, and you do get rock chips on your car.
It has perhaps a slight positive effect on the truck, or none.
This has been discussed sooooooo many times.
Do some research.
I hope that was a late "April Fool" joke Walt.....

 

You claim that the more weigh a vehicle (like a truck) pulls along behind it, its gas mileage goes up.

I claim that the more weight a vehicle pulls behind it, its gas mileage drops.

Well, I guess you and I will just have to agree to disagree.

 

LOL, so with that line of reasoning the UPS trucks you see on the thruway pulling tandem trailers must be getting better mpg than the single setups..........

While I can't really see that an Esacpe drafting a big rig would hurt the fuel mileage enough to worry about, I find it very hard to swallow that it would INCREASE the mpg......

~John

 

When I was coming back from my road trip I always looked for a good truck to "follow" (not necessarily "draft"). What was interesting was that most of the big rigs going in the right lane already had someone following them. So, this seems to be a pretty common practice- I can't imagine it bothers truckers, as long as you're 2-3 seconds back (which was what the driver's education program was teaching when I was a teen).

Also, truckers often follow each other, so it must be beneficial.

When I was cruising at 65mph on open road the scangauge usually read in the low 20's for instant MPG, but when following a semi it was high 30's.

I believe this can be a safe or unsafe practice, depending on how it's executed.

Those semi's need to pull that big box through the air- sitting in that wake can't possibly have an effect on their mileage!

 

Walt, are you hooking your FEH with a tow bar up to the truck in front of you or what?
Please tell me you are jokeing!

We are talking about WIND RESISTANCE.
No one knows what the heLL Walt is talking about!

I guess some people are just set in thier ways and don't care about reality.

 

I believe the THEORY would be that the huge wake creates a vortex or a semi-vaccuum that applies drag force to the back of the semi.... If another vehicle is in that area supposedly it will occupy some of the vortex area, reducing that drag force because the air doesn't have as much space to fill after it rushes in behind the semi-trailer. So the THEORY people often site is that it would HELP the semi ever so slightly.

You'd have to be pretty close for this to be true, and I'm not convinced its sound physics, but I think thats what people believe who think you'd HELP the semi.

 

Agreed. In 99.99% of all cases you will have zero effect on the truck.
In rare cases you could help the truck, but not enough to measure.
You will never hurt the truck's MPG.

 

I'm not a NASCAR fan, but NASCAR operate off of this principal. They pull up behind another driver (driver B) and draft him. It disrupts the downward force on driver B's car and also creates a vacuum that propels driver A past driver B.

 

Close, but not quite.

Drafting off a car in front, reduces wind load on the car in back... thus the car in back is no longer operating at maximum horsepower. It saves the car in back gasoline, and also gives him more "headroom" ( his foot is no longer to the floor, while the car in front is ) to accelerate and pass when the time is right.

I don't know why this is so difficult to understand.