(engine revving) - You ever wondered how that Amazon package
got delivered to your door? Well chances are it came in
the back of a semi trailer pulled by a semi truck. So today we're going
on a trucker's journey with the Peterbilt 579 Ultraloft, one of the most sophisticated modern day semi trucks to hit to the road. We're gonna look at a couple things. First the 5th wheel. We're gonna look at the
axles, the air suspension, and all that beefy looking
stuff that can withstand thousands of pounds of
weight pushing down on it. And finally we'll dive into
the heart of the beast, a 15-liter Cummins diesel engine that can pull 80,000 pounds for hundreds of thousands of miles. Semi truck big rig trucker talk, get ready for some trucker lingo. (hip hop beat) Big thanks to Raycon for
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order of Raycon earbuds. All right, we've just spend
the night in our sleeper cab. The morning has come, it's time to get to work. We scoot on down to the pickup site and today's load is 45,000 pounds of Panasonic PMV-939 TV VCR combos. So let's ese how we hook up
this trailer to our big rig. Now I know you guys
have been on the highway and passed by a big rig
without a trailer behind it and seen that round, big,
goo covered plate on the back and thought what the heck is that thing and how does it work and why is it covered in goo? All these questions pop into your head. Well, that's called a 5th wheel and it's the device that keeps the trailer connected to the truck. Now there are two parts of
this 5th wheel equation. There's a kingpin which is a two inch or three and a half inch
diameter vertical steel pin and that drops down from the bottom of the
front of the trailer. And then there's the 5th wheel which is the horseshoe
shaped coupling device on the rear of the semi. That's the goo-covered part. And why is it so gooey? Well that goo is grease. Now the flat plate on the trailer and the flat plate on
the fifth wheel hitch are in constant contact with another. So when the truck turns those two plates, they slide against each other like this. And if they didn't have
grease between them it would wear down, they'd
build up a bunch of friction, the front wheels actually,
your steer wheels, they would wear incorrectly. There's a lot of stuff that goes on when those aren't greased up. So underneath the 5th
wheel there's a mechanism that locks that kingpin into place, and what it does is those jaws, they rotate around the kingpin and the only way that
they can ever come undone is from a pull lever outside
which the trucker operates. That prevents that kingpin
from ever slipping out. And those jaws are made of forged steel so they are very, very strong. And when you do back that in it makes that click clack sound. (smacks) Man, that is such a cool noise. Only truckers can really appreciate that. But now you can appreciate it, take a listen. (mechanical clanking) So you got a honker of a truck
that weighs 18,000 pounds, an empty trailer that
weighs about 17,000 pounds, and packed into that trailer is 45,000 pounds of VCRs and TVs for a combined weight of 80,000 pounds rolling down the road. So how can a semi truck
handle all that weight? Well, it needs big, strong, heavy axles and heavy duty suspension. Now there are rules out there
that truckers have to follow that restrict the amount of
weight allowed over the axles of the tractor and also the trailer, which is why there's weight stations on the side of the highways. They got to check to make sure you're not going over
weight on any of your axles or total combined weight. Now in the case of the
Peterbilt 579 Ultraloft, is has tandem drive axles, so it can hold a maximum of 34,000 pounds on those rear axles. 34,000 pounds, that is an extremely
hard number to visualize. I have a F-150 and it
weighs about 5,000 pounds. So seven of my trucks can be stacked on the
back of that Peterbilt. Okay, if that doesn't help, just imagine 125 Nolans dancing
on the back of this truck and just being like "Yeah, uh." (laughing) I love you, Nolan. Now the 579's rear axles
have a 40,000 pound GAWR and that stands for
gross axle weight rating and it's the maximum distributed weight that may be supported by an axle. Now a Ford F-250 has a GAWR
in the 6,000 pound range to give some perspective here. So these semi trucks are
super, super heavy duty. Now that weight includes the vehicle, the driver and passengers, the cargo, all the fluids, all that stuff, and yes, the semi trailer load. So those axles are more
than strong enough to handle all that tongue weight. But what about the suspension? (engine idling) There are two types of suspension setups you see in a semi truck. There's the more traditional
leaf spring setup and the more sophisticated air suspension. Now I'm sure you know about leaf springs. They are used in a lot of pickups and they're made out of steel and they're bent in that
semi elliptical shape because that allows them to flex when there's pressure on
top of them or a load. Now the other is air suspension which comes with the Peterbilt 579. And they used air suspension
for a few good reasons. They provide a smoother ride with and without the trailer attached. They weigh less which
means you can haul more which is good, that means more money. And they have better load
handling capabilities compares to its leaf spring brethren. Also the bag acts as your spring. I mean they're literally
called air springs which means you can effectively
change your spring rate by changing the pressure in the bag. Also, it helps making loading and unloading a semi trailer easier. I'm gonna get to that in
a bit so stick around. Now air suspension systems
uses a variety of valves with air lines and airbags that replace all the steel
in the leaf spring setup. And these bags are heavy, heavy duty. They're made from a woven
and rubber-like material that's capable of handling
thousands of pounds of weight pushing down on top of it. And it does that under
relatively low pressures, anywhere from 15 PSI to 100 PSI. And that air is being
supplied by a compressor with external air takes like this one. Hold on, I'm gonna go get one. I'm gonna go get one. It's like this.
(clattering) It's like this, aw (bleep), I pulled it out of the wall. (bleep), I bend my god dang, god dang it. Anyways, it's like this, okay. You got one of these
honkers in your truck. But these tanks, they're bigger tanks than this. You have an air compressor
with a couple of, couple of auxiliary tanks. You guys get it, this
thing's (bleep) heavy. Now air ride suspensions
use a special air valve called a height control valve that controls the amount of
air pressure in the airbag. Now when a trailer is hooked up and more and more cargo is added the height control valve sees movement between the axle and the chassis. And as there's more weight
being pushed down on the axle it begins to squat, right. And once that axle height
reaches a certain threshold, the valve sends more air to
the air spring (mimics valve), it pumps it back up, bringing the axle back up
to the appropriate height. And that height is called the ride height. And when you're unhooking trailers you can use a dump valve
to depressurize the bag, dropping the truck so you can pull away
from the trailer easier. Makes truckers' lives
a little bit simpler. And they need it 'cause
they work really hard. Thank you guys. Now Peterbilt makes a ton
of different air suspension. There's the Air Trac, there's the Flex Air, there's the Air Leaf, there the Low Air Leaf, and there's the Low Low Air Leaf because that guy who named
it was running out of names. And now the reason there's so
many options is because, well, not all truckers haul the same stuff. But the overall principle on how they work is still the same. Now if you're wondering what if one of those bags fail? Well, inside the bag is
a solid piece of rubber or other type of plastic piece and it's engineered to prevent the load coming down and damaging the
truck in the case of a puncture or sudden loss in pressure
in the air spring. So we're loaded up, we're ready to make our
way from Houston to LA. You get on the CB radio, you tell your buddy Kentucky
Cobra "We're on our way pal." You push the air release button and your trailer brakes release. And then you throw the
key into the ignition, you give it a good crank, and you turn on 605 horsepower and 2050 foot pounds of torque out of this monster diesel engine. (jazzy hip hop beat) Now semi trucks can get specced out with all sorts of options. From the cab size to the engine size. And since I'm the one getting
to talk about the engines, we're gonna look at the X15 Cummins motor. Now it is a 15 liter, six cylinder engine. Yes, six cylinders. The size of the pistons are close to five and a half inches in diameter. Now to put that in perspective, this right here is a piston from a 250 CC, my RM 250 dirt bike. And it is about two inches in diameter. Now the Cummins X15 diesel engine, like I said, it has a piston diameter that
is five and a half inches. This is a pad you use to wax stuff on. Wax on, wax off. So that is the difference in
the size of those pistons. That's wild. And the engine alone weighs 3,000 pounds. It's built using really heavy, really strong parts
that are built to last. I mean heck, it doesn't even need a fluid change for half a million miles. Now when I was a kid I
always wanted to know why those big trucks use
the green gas handles. Well, first, young and dumb Jerry, it's not gas, it's diesel. But more importantly why do semi trucks use diesel engines? Well, it's because semi
trucks need engines that have tons of torque. Now torque is the twisting force that causes an object to rotate, you probably know that. And in the case of the auto world it's directly related to the ability of an
engine to pull a load. And pulling power is the name of the game when it comes to trucking. So you want peak torque at low RPM and that's exactly what
diesel engines give you. Now why is that? Well these semi truck engines
use big bores and long strokes and a ton of compression. The X15 Cummins has an 18.9
to one compression ratio, which means it jams a lot
of air into the cylinder especially compared to gas engines. And the more pressure you can build up in the strokes and the cylinders, the more torque the engine will produce. (engine revving)
(cheering) And it just so happens that diesel is also the perfect
fuel for high compression. Now unlike a gas engine
that needs a spark plug to light the air fuel mixture, diesel engines compress that air to such a high pressure and temperature that the diesel ignites
without the need for a spark. Now remember when you compress a gas you take it from a state
like here in the air and you bottle it up into a smaller area, you're compressing that air, it creates heat. That's why if you ever
used an air compressor and after it runs for a while you feel the sides of the tank, it's hot. Well that's because the air is getting forced into a
smaller space, a smaller volume, and part of the process,
it gives off heat. Now the temperature of
the air being compressed is greater than the auto
ignition temperature of diesel. Meaning that when the injectors squirt diesel into the cylinder it spontaneously reacts
with the oxygen in the air and a combustion takes place. Kaboom, not an explosion. I said that before, I apologize. Combustion, there's a difference. Explosion, you can't control. Combustion, you can. Diesel engines are also more efficient because diesel fuel
burns more efficiently. A gas engine is roughly 20% efficient, meaning 20% of the thermal
energy content of gasoline is converted into mechanical work. If we take a car with a 20
gallon fuel tank with gas in it, four gallons are actually
used to move the car. That remaining 16 gallons is lost to friction, noise, and heat. Now diesel engines on the other hand, they can get up to 40% efficiency range. And that's because diesel
burns steadily and faster. So if we have a gallon of
diesel and a gallon of gas, you have more usable energy in diesel. That means diesel trucks,
like the Peterbilt 579, can go about 20 to 30%
further on a gallon of fuel compared to its gas bro bro. Which means the duel 120
gallon tanks on this thing, 240 gallons total, can get you about 1,400 miles on a fill up when you're averaging
six miles per gallon. Six miles per gallon doesn't sound great, but that's actually
pretty good considering the amount of weight these
trucks are carrying around. So these engines fitted into semis, they have a very narrow power band, meaning they have a narrow
range of RPMs to work with. And the X15 is even governed at 2,000 RPM. So as a trucker you need to
shift the gears frequently to keep the engine running at the RPM that gives you the most torque. And to stay in that narrow power band you need a lot of gears that
steps you up to highway speeds. That's why in the olden days semis with manual transmissions
used as many as 18 gears. Now you've been behind a
truck before at a stop light, and when they go to take
off they're lurching forward and bouncing all around. And it's because the
person driving that truck is feverishly shifting through the gears. That truck's transmission
is probably in sixth gear by the time your car is
starting to shift into second. Now with some current day future tech, those manual transmissions
have been replaced with automatic ones. A 579 uses an automatic
12 speed transmission. And it does a few things different from a normal automatic
transmission in a car. For example, it will use data coming from the load sensors
in the rear of the truck to determine how much weight
is on your fifth wheel. It will then, based on that data, determine which gear to start off in. So say you have a light load, right, you're not carrying very much. It might start off as high as fifth gear. And these transmissions
talk to the engine. They look at the fuel map, they look at the engine load. Even the sensors that determine
the angle of the road. They are all used to optimize
which gear to shift into. And that helps the engine perform better as well as be more efficient. And just like the engine, these transmissions are beefy. It weighs close to 700 pounds and it's capable of pulling
loads up to 110,00 pounds. Aye, Kentucky Cobra, it's Florida Man. I'm parked out front, bundled out with 45 big ones above horse. Boy oh boy, am I a'swinging. Don't make me fingerprint
this one on my own, bud. (heavy metal music)
(guitar riff) - If there's anything youtubers
like me want to be in life it's a musician. Unfortunately I have no talent. But I won't let that stop me
from making my own band shirt. (heavy metal music) I'm super stoked that "Wheelhouse" finally has its own shirts and I'm double stoked on how it came out. I really wanted our shirt to emulate some of my favorite bands. It's got a haunted house on it 'cause it's "Wheelhouse"
and I'm a spooky boy. (heavy metal music) Also there's a lot of
"Wheelhouse" Easter eggs included on the shirt. Definitely a -- reference
on there somewhere. You got to look for it though. I love the shirt, I love how it came out, and you will too. You can get it on our store--
- Donutmedia.com. And live out all of your
headbanger fantasies. (heavy metal music)
