Dual wheels and Super Singles.

I am thinking about doing a series of posts about the trucks we drive. I have been toying with the idea of making videos to show the inspection process I go through on the trucks. Short videos which will highlight one item at a time. Explain the function of the truck part and what has to have a close look.

Of course, Joe will get roped in on this as well. The challenge will be to keep “Chatty Kathy” on a leash so he doesn’t do to you what he does to me. Start explaining something then get sidetracked off on a tangent that is not even related to what we are talking about.

Have you ever wondered why he has no hair? It is because I have thumped him atop his head often enough to get back on track. Not really, folks.

I’ll start this one off with a discourse on tires. Truck tires.

There are three types of tires that are mounted on trucks.

Steer tires are for the front wheels. I’ll show you Steer tires in a later post.

Drive tires are for the two rear axles. There is a total if 8 Drive tires on each “Tandem Axle” truck.

Tandem Axle just means two (2) axles working in conjunction with each other. Your car or pickup will only have a front and back axle.

Super Single tires are a recent addition to the semi truck tire line. Super Singles have been around about 7 years. They are supposed to weigh less than a set of Duals which allows for more cargo weight. Many trucking companies are using the Super Singles on their fleets.

Dual tires on tandem axles.

Super Singles on tandem axles.

There are advantages to both types of tires. The cost of one dual tire is about $600. To outfit a truck with new tires on the tandem axles has a cost of over $4800. Super Singles cost about $900 each and only four (4) are needed for a cost of $3600.

If one tire on a dual blows out the driver can have that one tire removed by road service and limp to the nearest truck stop – less than 20 miles – to have a new tire replaced. Or just have the tire replaced by road service while they are there.

When a Super Single blows out there is no limping anywhere. Another problem with Super Singles is keeping the tires pressurized to the proper air pressure all the time. Costly devices have been developed and installed on the trucks to have a constant air supply leading from each axle hub to keep the tires properly aired up.

It is up to the driver to check his/her tire pressures daily. This has to be done to keep the tires from blowing out due to low or uneven air pressure. Low air pressure causes the sidewalls of the tire to get hot and blow out. To much air pressure causes the tire to ride on the center of the tread and give uneven wear. These tires require constant and even air pressure at all times. Special steel or aluminum wheels have to be purchased for Super Singles as well.

Guess you can say Super Singles are “high maintenance” :-). The work horse tires are the Duals.

This ends the lesson on tires in the trucking industry :-). Now you can go take a nap 😜

Leslie

A bit of technical junk

The trucks we have today are Freightliners and are “Mid Roof” in style.  Which means the driver is able to stand up in the sleeper section and move about, take their clothes off without banging their head.  This is sometimes referred to  as “Stand Up Sleeper” because a person can actually stand up.

Our trucks yesterday were Kenworths and the style is known as “Condo” because it has bunk beds in the sleeper area.  A top bunk and a bottom bunk.  Condos are more spacious in design to accommodate more than two people in the truck at one time.  Although cramped quarters with two people….well the size of Joe and I anyway…there is still a lot of room in a Condo.  The Mid Roof style has only one bunk and very tight quarters for two people.

These are dual tires on a flat bed trailer.  I’m using it as an example of what the trucks we normally drive have for tires.  There are four sets of duals on each truck.  They are on the rear axles.

These are known as “Super Singles” and are a single tire on each side of the axles.  These are for heavy hauling, weights that exceed the normal 80,000 combined weight of tractor and fully loaded trailer.  These are on the trucks we are taking out of Gary, Indiana this trip going to Houston, Texas.

Joe just corrected me on what I had just stated on the Super Singles.  He says they are for better fuel economy because of reduced rolling friction that happens with the duel wheels on trucks.  I stand corrected.

This nasty piece of business is the gear shifting “Paddle” for the automatic transmission.  A  little yellow button slides up and down on the outside of the paddle to engage the gears from Reverse to Drive.  Unlike your car with a “Park” gear or “P” these trucks have to be put in Neutral – “N” – and the air brake handles pulled to put the truck in park.

Automatic transmissions…..I HATE them.  Unlike your vehicle when pulled into the gear you select, either Drive or Reverse, you are able to step on the gas pedal and go slow or fast depending on the amount of pressure you put on the foot feed.  The automatic transmission in trucks is a flipping beast to work, totally computer controlled.  Put it in gear then apply some gas to get the truck moving….nothing happens.  Then the blasted thing decides to kick into gear and you are OFF and RUNNING faster than you want to go.  Slam on the brakes to stop the fast momentum and then you get to go through the whole exercise again.  Going nowhere, easing into motion, then immediately going faster than you intended to go.

Backing into a parking spot, or under a trailer can be quite a chore with these automatic transmissions.  Joe and I have been able to know, just by looking at the condition of the rear of the cab, if the vehicle is an automatic transmission.

As for fuel economy they are the best thing out there.  For anything else, like city driving with traffic lights and/or stop signs, these transmissions are the worst.

As you travel around in your daily life, if you are beside a truck or behind one, watch to see how the truck moves.  If it is jerky and bouncy more than one time after starting from a full stop chances are good the driver has an automatic transmission in his truck.

FOR YOUR SAFETY, I beg you please….pretty please with a cherry on top.  When stopped behind a big truck at a traffic light, leave enough room between you and the rear of the trailer so you can see the tires on the pavement.  The rear tires of the trailer or the rear duals on the bobtail.  Automatic transmissions in trucks are notorious for not catching immediately and the truck will roll backward before it finally goes forward.  ESPECIALLY ON AN INCLINE!!!!!

You could find yourself pinned underneath the “DOT Bumper”, the hangy down thing at the back of trailers if you stop real close to the back of a truck and trailer combination.  You could also get the nose of your car bashed in by the rear frame of a bobtail.  More and more trucking companies are going to automatic transmissions because of the fuel economy savings in their bottom line.  So please be careful out there.

Leslie