N00b Questions You (Probably) Have But Were Afraid To Ask!

(I'm a non-driver studying for the written test.)

Q 11. Moving 5th Wheel: Why do this?

Here in BC Canada, the "Driving Commercial Vehicles" handbook states: "If the rear of the tractor is too close to the trailer landing gear and the tractor has a sliding fifth wheel, reposition the fifth wheel to provide clearance." pg82 http://www.icbc.com/driver-licensing/driving-guides/Pages/Driving-commercial-vehicles.aspx

Question 11 was answered earlier as adjusting weight distribution between front and drive wheels, to set the weight at the steering axle to be under 12,000 lbs, I believe. Thank you, that makes sense.

I just found this thread (7 months later...), but I can help with #8.

My mom won't go anywhere without em. Even when renting a car for a couple hours she puts them on. I've seen tons of deer skitter off. Meanwhile, in my dad's car without them, they've ran out in front like we're invisible. They work!

Mike I can honestly state I've never moved a fifth wheel in order to clear the landing gear. Most of the time our equipment is matched fairly well. In my LW tractor I run with the fifth wheel in the front most notches. Plenty of room the shimmy in front of the landing gear to check for a positive lock.

I wrote this in response to Miss Miyoshi's post to question 11:

As already stated, balance. The goal is to be as close to 12,000 pounds on the steer axle as possible, as a side benefit slightly increases the weight ceiling on the drive axles. Important when dealing with a 45k+ lading weight. The "sweet-spot" where 11,500-11,800 pounds is achieved on the steers, all depends on the tractor. Usually after a couple of attempts on the scale (loaded), once found, typically not necessary to ever move it again.

I knew the owner of a small trucking company who had at least one deer strike every hunting season until he installed the whistles. Not scientific proof but ...

As for the differential lock. I found this explanation on the Web that explains it better than I could.

The inter-axle differential (IAD) lock is also known as the power divider or power divider lock (PDL), or “diff lock.”

The inter-axle differential lock or Power Divider is for use in low-traction situations only. Read your operator’s manual for full instructions an specifics!

The inter-axle differential is not meant for use on dry pavement.

The inter-axle differential lock can be engaged while in motion (as when approaching a slippery hill) as long as: — The wheels are not spinning, or — The vehicle is not on a curve or in a turn.

An inter-axle differential (IAD) works in a similar manner to the main differential (splitting power between the two wheels), except it splits the torque equally between the two axles of a tandem , rather than the two wheel ends of an axle.

What happens if you engage the diff lock when the wheels are spinning? You may hear a grinding sound and feel vibration while the diff lock tries to engage.

What happens if you leave the diff lock on while driving? Driving with the diff lock on will cause high stresses and strains in the drives, and can result in accelerated component wear or even catastrophic failure.

To Use The Inter-axle Differential Lock Flip the switch and press the clutch briefly (some recommend to feather the clutch, as in a normal shift); do likewise to disengage the lock.

Caution: You should not activate the differential lock when the wheels are spinning (when traction has been lost and/or the tandems are rotating at uneven speeds).

How often do you drivers weigh your fuel. That's where I'm at in the High Road training and made me curious.

Jim asks:

How often do you drivers weigh your fuel. That's where I'm at in the High Road training and made me curious.

6.943 lbs per gallon.

G-Town I know the weight of the fuel (the high road says to figure 8lbs per gal) but I was more interested in how often you guys actually weigh fuel added per lbs on your steers. Basically are you loaded that close as to be overweight on you steers sometimes adding fuel?

Jim asks:

How often do you drivers weigh your fuel. That's where I'm at in the High Road training and made me curious.

6.943 lbs per gallon.

Okay. Although 8 is a little higher than ANSI per gallon rate of diesel, it's a safe number to use for estimation purposes.

I scale at the D.C. after getting my load. With full tanks (200 gal) and loaded, I have never been over 11,600lbs on the steers. I gave you the weight of the fuel because that is how we figure the amount to take-on (if close to max weight) and the burn rate. For instance if my GCVW is 79,200 leaving the D.C. and I need to fuel, I won't take on more than 75 gallons before my first stop.

Unless driving an older Prostar (tanks were far forward), weight of fuel has a greater effect on the drives.

I'd like to ask for any advice or tips on a situation that almost turned catastrophic on me a few weeks ago.

I am a new driver in Primes team driving (TnT) phase of training. I was traveling West bound on I-80 West of Cheyenne WY. Road conditions quickly deteriorated after I passed Cheyenne. High winds started blowing snow across the road. Temperature was below freezing and black ice warnings started flashing on highway signs. I was approaching a steep decent with a group of other trucks. I had been instructed in slippery decents to just go very slow, use light engine braking to control vehicle speed, and avoid using the service brakes. If necessary use them very gently. I let the group of 3 trucks get about 200 yards ahead of me and I was attempting to hold a speed just a bit under 20mph using light engine brake. The truck is an automatic, and the manual mode on Primes automatic trucks are disabled. You can force an upshift, but it will just shift itself back down a couple seconds later. It was explained to me that using light engine brake was the only way to get the truck to hold a gear into high rpms. Without it the truck just keeps down shifting to the most fuel economical gear. I had what felt like a stable decent speed of around 18-19mph when the road started curving left. During the curve I felt the tractor lose traction and the trailer started pushing me sideways. My eyes shot open, hands clamped onto the wheel, and butt bit a chunk out of the seat as I realised im jackknifing. I quickly slapped the engine brake off, counter steered and was able to get the truck straight. Without the engine brake the truck shifted into a higher gear and started accelerating under it's own weight, so I very gently applied service brake to gradually slow the truck down under 15 mph. A few moments later I noticed the CR England truck a ahead of me experience the same problem as they nearly jackknife. Now im to afraid to use the engine brake because I nearly jackknifed, but I know riding the service brake down isn't exactly a great idea either. I ended up using a pattern of staying off the brake until 15 mph and then applying brake till under 10 mph, over and over again until I got down the hill. I was very concerned about the brakes heating up, but I made it.

Shortly after completing the hill we got stuck in standstill traffic because someones trailer up ahead had caught fire. I listened on the CB as driver's commented that some idiot probably rode their brakes down the hill.

Later when traffic started moving my gut sank as I passed the truck. Their trailer had indeed caught fire right above their driver side trailer wheels. The kicker was.... ... It was another Prime truck. And a later model Freightliner, probably an automatic, just like I was driving. Probably had my same issue.

I'd like to ask for any advice or tips on a situation that almost turned catastrophic on me a few weeks ago.

I am a new driver in Primes team driving (TnT) phase of training. I was traveling West bound on I-80 West of Cheyenne WY. Road conditions quickly deteriorated after I passed Cheyenne. High winds started blowing snow across the road. Temperature was below freezing and black ice warnings started flashing on highway signs. I was approaching a steep decent with a group of other trucks. I had been instructed in slippery decents to just go very slow, use light engine braking to control vehicle speed, and avoid using the service brakes. If necessary use them very gently. I let the group of 3 trucks get about 200 yards ahead of me and I was attempting to hold a speed just a bit under 20mph using light engine brake. The truck is an automatic, and the manual mode on Primes automatic trucks are disabled. You can force an upshift, but it will just shift itself back down a couple seconds later. It was explained to me that using light engine brake was the only way to get the truck to hold a gear into high rpms. Without it the truck just keeps down shifting to the most fuel economical gear. I had what felt like a stable decent speed of around 18-19mph when the road started curving left. During the curve I felt the tractor lose traction and the trailer started pushing me sideways. My eyes shot open, hands clamped onto the wheel, and butt bit a chunk out of the seat as I realised im jackknifing. I quickly slapped the engine brake off, counter steered and was able to get the truck straight. Without the engine brake the truck shifted into a higher gear and started accelerating under it's own weight, so I very gently applied service brake to gradually slow the truck down under 15 mph. A few moments later I noticed the CR England truck a ahead of me experience the same problem as they nearly jackknife. Now im to afraid to use the engine brake because I nearly jackknifed, but I know riding the service brake down isn't exactly a great idea either. I ended up using a pattern of staying off the brake until 15 mph and then applying brake till under 10 mph, over and over again until I got down the hill. I was very concerned about the brakes heating up, but I made it.

Shortly after completing the hill we got stuck in standstill traffic because someones trailer up ahead had caught fire. I listened on the CB as driver's commented that some idiot probably rode their brakes down the hill.

Later when traffic started moving my gut sank as I passed the truck. Their trailer had indeed caught fire right above their driver side trailer wheels. The kicker was.... ... It was another Prime truck. And a later model Freightliner, probably an automatic, just like I was driving. Probably had my same issue.

hi and sorry for your experience. so glad you are ok and safe.

first off, you probably should have been parked in those conditions. things do change rapidly there, but it is usually forecasted so checking the weather with apps like National Westher Service, Weather Channel, and WY511 are huge helps. if i was your trainer, you would have been parked.

second, you just learned a huge lesson. You were able to keep calm and stay in control. you were terrified, yet still thought without panicking. great job!!!

one issue with the automatics: experienced drivers tell me they shut down sooner than before for exactly this reason.

Im still in a manual, so I hooe someone comes along to discuss this in the autos. but as for brakes/tires catching on fire...it happens in manuals as well.

ive seen 3 seperate trucks on fire at the bottom of downgrades. stupid cause everyone is in a hurry. slow down and go easy.