Drafting a Semi for better mileage

[Sparky]

http://i.imgur.com/8NHihyk.gif

[Smokinjoe-VRCCDS#0005]

I haul heavy equipment for a living.... I've had tires blow off the rim as well.... Think about that the next time you ride behind or beside a tractor-trailer 

[cookiedough]

but you know by drafting a semi, it has been proven by Mythbusters to save on gas mileage significantly up until less than 10' behind. (for those who don't value their lives that is).

I have tried going on my cycle say less than a 3 second following distance behind a semi on a straight road that I know doesn't have much traffic.  I don't like it, the wind currents toss you around even on my Valk I/S like a wet noodle side to side.  

[Oss]

I noticed when out in Colorado that a double or triple semi can make
a big disturbance in the air a quarter mile ahead of you

Its a good thing that a Valkyrie can pass them easily especially in the rain when the spray
can be drenching

Why anyone would WANT to have their view of the scenery ahead of them is beyond me

[The emperor has no clothes]

I haul heavy equipment for a living.... I've had tires blow off the rim as well.... Think about that the next time you ride behind or beside a tractor-trailer 

When I was 14 and started riding a Suzuki 90, I found I could hit 70 or whatever the truck driver would do by drafting up tight to the back of a semi. One time I hit a pothole that I didn't see because of doing that and went into a tank slapper. Never did it again. God does look out for fools.

[YoungPUP]

Having a tire blow off is scary.  How do you describe when sh*tty Maintenance causes a set of duals with the drum still attached to leave the vehicle at highway speed.... 

[..]

I've been in groups where other riders seem to be happy being next to the middle of an 18 wheeler  

I hang back until the rider ahead is clear and then get past the semi cleanly and quickly.

On 2 lane roads with an oncoming 18 wheeler I will move to the right of my lane to get away from anything coming from the semi, to get away from the turbulence behind, to move away f\rom anything being thrown up by the semis wheels and to let any following following vehicles see me so they don't try to overtake the semi.

[Bighead]

i was beside a semi year before last somewhere in  pennsylvania and a tire let go right beside me. Scared the dog crap out of me I dropped a gear and hammered the throttle

[old2soon]

Out on I-10 in New Mexico years ago I had a recap on the trailer I was not proud of. A lime green pinto insisted on hanging out right next to the tire in question. He had a C B radio and I asked him a few times to either pass or drop back. He did neither. The tire le loose but the cap stayed attached to the casing and beat the front end of that pinto half to death. He went into the center media and I stopped on the shoulder to see if they were o k. They were talking suing me the company and anybody else they could think of. As the tirade was increasing a N M state Trooper pulled up. He had been behind me and heard my warnings to the pinto to back off. Told me to go on about my business and he would take care of the folks in the pinto. NEVER did hear anymore about it!  RIDE SAFE.

[hubcapsc]

I haul heavy equipment for a living.... I've had tires blow off the rim as well.... Think about that the next time you ride behind or beside a tractor-trailer 

When I'm in a group and we're passing a big truck, I wait for the guy in front of me to
get all the way past, and then I nail it and get by the truck ASAP. That tire in the gif
came off when he hit a pothole...

-Mike

[Hooter]

I won''t ride behind a semi any longer than I have to. If I have to I back off. I like to see whats in front of me and just for the reason shown in the clip. Retread or recaps or what ever  you want to call em are all over the place around here.

[musclehead]

I've been on both ends of that, losing a tire like that makes you instantly think "UH-OH LAWSUIT!"

seeing them fly off with force enough to go through a windshield, don't be that guy!   mud flaps are only so much protection, tires flying off rims have a LOT of force.

[old2soon]

Having a tire blow off is scary.  How do you describe when sh*tty Maintenance causes a set of duals with the drum still attached to leave the vehicle at highway speed.... 

       In my truck drivin career I've had all manner of "stuff" depart the vehicle. ALL of it was mechanical that became detached. NEVER ONCE lost any freight. I lost the outside dual off of a trailer going into Lost Wages Nv. one day and spent about an hour and a half looking for that tire/wheel combination. My wife was with me and we never did find that thing. And it was the scrub desert where I lost it. Bright sun shiny day and that wheel-inside and outside was painted international orange!  If folks insisted on tail gating me I did one of 2 things. Heavy traffic I'd slow down til they got tired of that game. If I was out in the wide open wide open and had a triple digit truck-over 100 M P H capable-I'd find out HOW serious they were bout walkin the dog! Walkin the dog-old trucker term for goin REALLY fast!  Back in the 70s and 80s was NOT uncommon out West to see a LONG string of trucks runnin out in excess of 90-95 M P H and eatin miles and havin fun!  BUT having been a professional driver I agree with the folks the get around a semi QUICKLY-DO NOT dawdle.  And fer sure and fer certain-DO NOT under ANY circumstances "hang out" next to a semi while rollin down the highway. NOT a good plan!  RIDE SAFE.

[czuch]

As much as I dig the profile as I blow past a big silver tanker, its really all buisness.
When I was in Driver Training it was 1 second for every 10MPH. When did that change?
 I swear some of these little pimply faced texters drive like theyre NASCAR trained.

[Rams]

Yep, it's true, you can draft and get better mileage behind just about anything, not just tractor trailers but, when something goes wrong, I doubt anyone will be sympathetic to your cause.    

One word of advice though, never, I mean never ever tailgate a cattle truck.   If you don't already know why, once should be enough.  

Play Stupid Games, Win Stupid Prizes.

[Willow]

One word of advice though, never, I mean never ever tailgate a cattle truck.   If you don't already know why, once should be enough.   

          

[JC]

Lost a good friend that had just retired a few years back to a tire core that was thrown from a big rig. He was on a Goldwing following the rig when the tire blew, and he couldn't avoid it. He died at the scene. Had one blow out as I passed it with the wife on the back, she thought we'd been shot. I'll never follow directly behind one, and accelerate to get past them when riding beside whenever possible just for that reason.

[Mobile Mayor]

About that cattle truck.   When I was much younger, we had a large straight bed cattle truck.  Dad and I were taking a load of cows and heifers to market.  A very ill tempered ugly fat woman began to pull out from a parking spot, apparently without looking.  Dad had to swerve to keep from raking her front fender, and he also laid on the horn.  Her response to the horn was sticking her head out of the window of her door, screaming "Stick it up your ass, you mo$#@$%&&&&tch.  I was riding shotgun and I looked out to the rearview mirror on my door, to see that one of the cows apparently was just the right height that her water discharge point matched the height of the space between the body slats.  It looked like someone had a hose shooting it out of the truck.  The ill tempered "lady" got the golden shower of cow piss.  Dad & I couldn't stop laughing the rest of the way to the stockyard.

[..]

Never ride close behind a horse trailer.

Those grassy cannonballs explode when they hit blacktop!!!

[GotValk]

I won''t ride behind a semi any longer than I have to. If I have to I back off. I like to see whats in front of me and just for the reason shown in the clip. Retread or recaps or what ever  you want to call em are all over the place around here.

I've had a smaller Van spit up a retread that was laying on the road , good thing I duck quick enough that would have left a mark...come to think of it , it did ........my shorts.

Be careful out there!

[Jess from VA]

Riding 50 feet behind an open pig truck smelled worse than................ well worse than anything I ever smelled.  It really went beyond smell into the chemical warfare arena.  Four of us on bikes were choking, losing vision, and laughing..... and slowing down.  A mile was just about enough.  GAG>

We decided to go in another direction.  

Too bad Pennsylvania Avenue is closed.

[Rams]

Riding 50 feet behind an open pig truck smelled worse than................ well worse than anything I ever smelled.

You have lived a blessed life haven't you.   

[Firefighter]

Years and years ago, I was riding a 1978 Honda 750, too close behind a car on the expressway and all of a sudden the car passed over (straddled) a muffler laying in the middle of my lane. It was by luck only, that I didn't hit it. Wasn't much time from when it appeared from under that car till I was on it. I learned not to follow too close that day!

 Following a pickup truck once an extension ladder fell out the back, but I had time to get out of its way.

On that same Honda 750, my wife on the back, I saw a tire and wheel, fall off the top of a station wagon that was more than a quarter mile away. I saw it bounce looked like fifty feet in the air and then start towards us at hi-way speed. The station wagon was traveling in a opposite direction than me. This wheel assembly came across the grassy median and I first slowed down then speeded up, and it passed behind me like a rocket. Wife never saw it, believe it would have hit me if at night or I was looking the wrong direction. Pucker factor was about a 9.7 as I remember.

About two years ago riding my IS I was again too close in slower traffic and a very dead and rank opossum appeared in front of me just like the muffler and I hit it and smell was right now as it burned on the header pipes. Thought I had already learned that lesson. Be careful.   Firefighter

[art]

Never tailgate anything on a bike.In 1993 when I just got back into riding I bought an 89 wing. It had a CB radio like most wings had then. We lived 30 miles from Palm Springs,Ca and while on a ride home from a meeting with some GWRRA friends I was following a friend on his wing. I was a little nervous since it was a long time since my last riding experience (25 years) . I radioed my friend to move over one lane to the left  We were riding in the lane next to a trailer truck up ahead. Just as we moved over the truck hit a piece of sheet metal about 4'x4' and lifted it up like a Frisbee and at windshield height in the lane we just moved out of. We both would died right there if I had not spoken up. DO NOT TAILGATE .  Did anyone ever see what comes out of the back of a truck after it hits a dead animal? It's not nice.

[Jess from VA]

Riding 50 feet behind an open pig truck smelled worse than................ well worse than anything I ever smelled.

You have lived a blessed life haven't you.   

If you mean.... bless his heart.

Well thank you.   

I've smelled dead bodies too (not as bad as that pig truck).

[HayHauler]

I was once riding with T-bar and he told me about those flying tires that can blow up on trucks and trailers.  He showed me how to give them a wide berth and get by as soon as you can. 
Great advice. 

Hay
Jimmyt

[old2soon]

Traveling on a 2 lane in Ks. one time in July or August behind a truck that goes out to the ranches and picks up the dead cows/horses/bovines. At the time I was following him he had a partial load on! GAG. Found a wide spot and gave him about 10 minutes. THAT particular odor was NASTY. RIDE SAFE.

[hubcapsc]

It is quite obvious that none of y'all have ever been at the Philips Motel when
they drain the grease trap at the restaurant next door  ...

-Mike

[The emperor has no clothes]

It is quite obvious that none of y'all have ever been at the Philips Motel when
they drain the grease trap at the restaurant next door  ...

-Mike

Worst smell I've ever been subjected to was cleaning grease traps in meat depts. And if the smell wasn't enough to get you sometimes you would get lucky and have 2" of maggots crawling all over the top of 100 lb. of rotting meat & fat. Oh it brings back great memories

[Rams]

If you mean.... bless his heart.

Well thank you.  

I've smelled dead bodies too (not as bad as that pig truck).

You're welcome Jess.

Know this, to someone, that pig truck was the smell of money and to them, that's one fine scent.  

Traveling on a 2 lane in Ks. one time in July or August behind a truck that goes out to the ranches and picks up the dead cows/horses/bovines. At the time I was following him he had a partial load on! GAG. Found a wide spot and gave him about 10 minutes. THAT particular odor was NASTY. RIDE SAFE.

Depending on the ripening time, I've seen some very strong people gag over the stench coming from the death wagons.   But, we've veered off course, I agree, let's not tail gate. 

[3fan4life]

Back in the 80's riding a CB750F I would routinely tuck in behind a semi in cold weather to cut some of the wind.

Until one morning I was riding behind one when it hit a deer.

That dang forest rat shot out from underneath the trailer like it had been shot out of a cannon. It missed me but I don't know how. That pretty much ended my tailgating days.

Pulling a camper behind my pickup I can get a 10 mpg increase in fuel mileage if I follow behind a semi.   

[czuch]

I got stuck behind a pig hauler on the Chesapeake tunnel, bridge complex.
Now THAT was a treat.

[wiggydotcom]

I would think following a big rig would tick off the driver-and rightfully so. Not only can't they see you but you're sucking their gas mileage down by creating a drag, especially if you're in a car. I've seen semi drivers lockup their trailer brakes to get rid of such parasites in cars.

[Gryphon Rider]

I would think following a big rig would tick off the driver-and rightfully so. Not only can't they see you but you're sucking their gas mileage down by creating a drag, especially if you're in a car. I've seen semi drivers lockup their trailer brakes to get rid of such parasites in cars.

Sorry, but from a fluid dynamics perspective, a vehicle tucked in behind another isn't going to increase drag for the lead vehicle.  In fact, having a trailing vehicle in the slipstream may reduce the negative pressure behind the lead vehicle, thus requiring LESS power from the lead vehicle.

[wiggydotcom]

I would think following a big rig would tick off the driver-and rightfully so. Not only can't they see you but you're sucking their gas mileage down by creating a drag, especially if you're in a car. I've seen semi drivers lockup their trailer brakes to get rid of such parasites in cars.

Sorry, but from a fluid dynamics perspective, a vehicle tucked in behind another isn't going to increase drag for the lead vehicle.  In fact, having a trailing vehicle in the slipstream may reduce the negative pressure behind the lead vehicle, thus requiring LESS power from the lead vehicle.

Ok, I stand corrected then. Thanks..Guess that's  why I never took physics in high school. 

[old2soon]

I would think following a big rig would tick off the driver-and rightfully so. Not only can't they see you but you're sucking their gas mileage down by creating a drag, especially if you're in a car. I've seen semi drivers lockup their trailer brakes to get rid of such parasites in cars.

Sorry, but from a fluid dynamics perspective, a vehicle tucked in behind another isn't going to increase drag for the lead vehicle.  In fact, having a trailing vehicle in the slipstream may reduce the negative pressure behind the lead vehicle, thus requiring LESS power from the lead vehicle.

      Watch NASCAR at the restrictor plate tracks. The rhumba lines go faster than an individual car. And them boys got the art of drafting down pat!   RIDE SAFE.

[wiggydotcom]

I would think following a big rig would tick off the driver-and rightfully so. Not only can't they see you but you're sucking their gas mileage down by creating a drag, especially if you're in a car. I've seen semi drivers lockup their trailer brakes to get rid of such parasites in cars.

Sorry, but from a fluid dynamics perspective, a vehicle tucked in behind another isn't going to increase drag for the lead vehicle.  In fact, having a trailing vehicle in the slipstream may reduce the negative pressure behind the lead vehicle, thus requiring LESS power from the lead vehicle.

      Watch NASCAR at the restrictor plate tracks. The rhumba lines go faster than an individual car. And them boys got the art of drafting down pat!   RIDE SAFE.

Yeah, you are correct. But I had also heard that a flock of geese keeps trading off their lead bird. With all that drafting, why is he getting tired? You don't hafta answer that, I'm just rabble rousing.

[..]

I would think following a big rig would tick off the driver-and rightfully so. Not only can't they see you but you're sucking their gas mileage down by creating a drag, especially if you're in a car. I've seen semi drivers lockup their trailer brakes to get rid of such parasites in cars.

Sorry, but from a fluid dynamics perspective, a vehicle tucked in behind another isn't going to increase drag for the lead vehicle.  In fact, having a trailing vehicle in the slipstream may reduce the negative pressure behind the lead vehicle, thus requiring LESS power from the lead vehicle.

      Watch NASCAR at the restrictor plate tracks. The rhumba lines go faster than an individual car. And them boys got the art of drafting down pat!   RIDE SAFE.

Yeah, you are correct. But I had also heard that a flock of geese keeps trading off their lead bird. With all that drafting, why is he getting tired? You don't hafta answer that, I'm just rabble rousing.

A different kettle of fish.

http://en.wikipedia.org/wiki/Drafting_(aerodynamics)

Flocks of geese and some other birds fly in a V formation because the wingtip vortices generated by the front bird will create up-wash circulations. The birds flying behind will receive lift force from these up-wash vortices. Thus other birds in the flock do not need to work as hard to achieve lift. Studies show that birds in a V formation place themselves roughly at the optimum distance predicted by simple aerodynamic theory

[Gryphon Rider]

Yeah, you are correct. But I had also heard that a flock of geese keeps trading off their lead bird. With all that drafting, why is he getting tired? You don't hafta answer that, I'm just rabble rousing.

Because while the lead bird may be using less energy than if it were flying by itself, it is still working harder than the birds behind it.  When it's had enough, it moves back in the line.

[MP]

I haul heavy equipment for a living.... I've had tires blow off the rim as well.... Think about that the next time you ride behind or beside a tractor-trailer 

YES!  When I rode my first Valk home from SC, there were two HD's drafting a semi.  I stayed back a ways.  After 10 miles or so, they turned off.  It was not 5 miles before he blew a trailer tire, and pieces went all over behind him. If they had not turned off???????

There is an additional hazard.  If there is debris, pieces of tire, etc., in the road, I just straddle them with my Peterbilt.  If you are 10' behind a semi, at 65 mph, are your reactions fast enough to avoid that 30 pound chunk of tire tread?  I think not.

MP