Huggin' Tailpipes
 

Today I was motoring my way up to the grocery store when a tractor trailer rode up behind me and started riding up my tailpipe. At first I was a little annoyed, but thought about drafting. I've read the threads of the gains people experience while drafting trucks. How about the other way around? Is it possible to have a gain with a large truck directly following behind you? You see these NASCAR races with the driver in front being able to go faster when someone drafts behind him. What do you think?

drafting
 

If I was a state trooper and witnessed that,I'd arrest the driver,impound his rig,pull his CDL,and lock him up for a minimum of 72-hours,just to let him think about whether or not he really wanted to be a truck driver.--------- He might have just as well pointed a loaded pistol at your head.Regardless of any potential for fuel savings ( which I would consider dubious ) his act was sociopathic.Very,very,dangerous!!!!!!!!!!!!!!!

aero: perfect response.

You'd have to literally have the guy in back on your bumper to reduce your wake, I'd think, in a normal car. I think the way being tailgated changes your driving habits would likely outweigh any aero benefits.

It would be interesting to see a group of the "best" hypermilers practice driving in a train, maybe with some radios, and see how their mileage could be improved. Only the best racers can draft within inches because when it comes time to hit the brakes, you've all got to be in very good sync. When I take my car to the track there are very few drivers (everyone is ametuer) that I would follow within 5 feet. Some drivers I wouldn't follow within 50 ft (not joking).

I typically follow that closely.







(while going <10 mph) not dangerous, but probably will eventually lead to me bumping someone.

Theoretically, you cutting his airflow and starting it around is truck will , at best, be more beneficial to him than you. Remember, he is screwing up that clean airflow you tried so hard to straighten out behind you. You would have to change your car to be essentially a wedge, at which point your mileage would be crap. To really get a mileage increase, just find a way to ask him to push you while your engine is off. What could go wrong with that, right?

ps- instead of trying to improve mpg, the driver was probably just wishing that damn slow-poke would get out of his way :wink:

I get this all the time. Theyll do 20 over the limit and fly up on you and just ride you for miles. Then pass when a car is coming and nearly cause a head on collision.

Im serious about the 20 over thing too, I travel US20 out here constantly and its a 55mph 2 lane highway in crappy shape. I got behind a truck one time and saw the speedometer at 70-75 and crapped myself. Theres no way the guy could stop if he needed to in less than 250-300 feet.

I got it once. I was doing 80 km/h in a 90 km/h zone when an empty big rig decided he was in a hurry to get home. All I would see in my rear view mirror was his grille. Mileage jumped from 75 mpg to over 90 mpg while he was riding my bumper.

The theory is sound. You have high pressure at the front, and low pressure at the back of your vehicle. The higher the pressure differential the higher the drag. Get something back there to fill the low pressure zone and down goes the drag. That's why 2 vehicles traveling in a convoy have less drag combined than the sum of their individual drag.