Semi Drafting: Something for those of you coming from afar to the north meet

[Thor06]

Hey guys, I was watching Myth Busters the other day and saw this awesome episode. They found the drag reduction at several different distances behind a semi, and the corresponding fuel efficiency change. I looked up on their site and found the data:

http://mythbusters-wiki.discovery.co...g+Rig+Drafting

I should note that I believe the drag was reduced by like 98% at 2 ft, but the pedaling necessary to keep that up is what did in the fuel efficiency at 2 ft.

It was on a newer Dodge Magnum at 55, so I dont think it'll be directly correspondant to a DSM at normal highway speeds but it should be a close guess. I'd never follow at 20 ft, but 50 feet is the distance from the tip of one road stripe to the next and that is definately doable. It'll feel close, but when you think about it if that big rig were to lock them up it would still take like 4x more distance to stop than our cars... it shouldnt be a big deal at all. I'd feel bad for the trucker, but I will have a CB installed shortly so I can let them know. When you think about that, if you get 25 mpg highway a 20% increase puts it up to 30 mpg. Thats an extra 60-70 miles per tank, and thats assuming that you're not having a higher drag reduction at the higher speed.

Just thought you guys might find that interesting/helpful to keep fuel costs low on the way over, I know for damn sure I will be following one!

[tfoti]

I do this on the way to work sometimes. But i get the feeling the truckers get pissed off at me. I think I'll bring my hand held CB radio too.

[gthompson97]

Truckers absolutley hate when people do that. I know when we haul stuff over the road, that's one of the things that pisses me off the most is when people ride my ass to get a few extra MPG.

[david-b]

Ya I've done that numerous times too. Not safe in my book but it does work. I'll just draft Brian... not Tim though. His little square 1G isn't aerodynamic anyways.

[JScharF]

My dad is a truckdriver and absolutely hates it when they get close enough to the point where he loses sight of them in his mirrors because the flatbed covers them up when they get so close.... and that was when he wasn't loaded.

[vanilla gorilla]

I never ride people asses but one day i did accidently observe some effects of drafting.

I dont remember the exact numbers here, but i was following closely behind a big truck (a six wheeler with a boxed in bed) doing fifty and i looked at my throttle percentage on my SAFC and it was 9%. So basically I had to give the car 9% throttle to go 50mph. Then I backed way off from the truck, and got back up to 50mph, but this time being in the open air, I had to give the car 12% throttle to run the same speed. So yes there is a difference.

[72chevelleOhio]

I know you guys will do what you want anyway but....

Its not safe to tailgate, blah blah blah.... you know that part.......

.....I have been wrenching on big trucks for years, just when I think I seen it all, something else comes in. If you are going to draft a big rig, choose VERY carefully which one you pick. You'll still be in danger, but not as much if you consider this.....

A big truck is a company vehicle. It gets treated as a company vehicle. "I don't give a f**k, its not mine" (yeah, I'm guilty of that too )

See those chunks of tread along side the road? That tire came apart with some pressure behind it, up to 110 psi. If your lucky it won't be a super single (the really wide ones found on some fire, dump, trash and tow trucks) those have up to 130 psi in them. But they are getting popular on the rear of regular trucks for increased MPG's...

I've also seen rusted out brake chambers. They are the parking brake for the truck. If something happened where it could bust out. (like the retaining clamp rusted out) It has more then enough power to literally go through a block wall. I have heard several stories of guys getting killed when they tried to take a chamber apart. (the wrong way) Theres a huge coil spring inside. "bigger" then your cars suspension spring, its not quite as long, but way more powerful!

Trailers generally get the least amount of care. Even if the truck looks nice the trailer could be total crap as far as service goes.

Just going by what I have seen, for the best "luck", I would choose a truck and trailer that is all polished up, no scuff marks etc. If it looks like hes been keeping the appearence nice, chances are the maintence is good too. Just because it looks old does not mean its junk. BUT if it looks like junk, chances are, it is! (even if its new it could be junk too!)

....All I am really trying to say is be careful!! Theres a lot more to it then just "what if the truck has to stop"

[steviek]

I don't bother following trucks couldn't care less about gas mileage I just want to be able to go as fast as I want.

[SilvrEclipse]

Its not worth the risk of getting hit by a tire or all the damn rock chips your going to have.

[Thor06]

Originally Posted by SilvrEclipse

Its not worth the risk of getting hit by a tire or all the damn rock chips your going to have.

You apparently havent seen my front bumper then.

[david-b]

Originally Posted by Thor06

You apparently havent seen my front bumper then.

Mines getting painted as we speak... so I'm going to try to avoid having thing hit it.

[tfoti]

Originally Posted by david-b

Ya I've done that numerous times too. Not safe in my book but it does work. I'll just draft Brian... not Tim though. His little square 1G isn't aerodynamic anyways.

You couldn't keep up anyways