Prime Trailers And Tandems

I'm terrible at titles, but I wanted to discuss weight distribution on Prime trailers specifically as this is my only experience so far in the trucking industry. So to start when I was in training my trainer told me 500 pounds per hole, I took this for granted as the holy bible until I read on here 400 pounds per hole and started to question things. So when scale tickets showed me that my 500 pound per hole slide was wrong I just rolled with the 400 per hole and didn't think anything of it until the other day when I had a load from a shipper with private scaling. One of those scales where you have to do the math yourself. So I roll my steers on, record the weight, rolled forward to drives on, record. Rolled the whole truck and trailer on, record. Here is what I came up with off the scales. Tandems as far forward as possible, so 3rd hole for this specific trailer: Steers: 11460 Steers + drives(truck): 43140(31680 on drives) Tractor + trailer: 78060(34920 on tandems)

Now given this and my 400 per hole assumption, and the fact that I was on 3/8 fuel I slide 4 holes back to the 7th hole, doing my math that should put me at this: Steers: 11460(minor change in weight not worth mentioning with tandem shift) Drives: 32880 Tandems: 33720 Obviously I am setting up so that when I fuel up and add 1000 pounds to the drives I am still legal.

Since I am a new driver my FM asked me to scale it out to check my weights, I figured sure what the heck the company is paying for it. Might as well give him what he wants. Cat scale ticket was as follows:

Steers: 11320 Drives: 33400 Tandems: 33280 Total: 78000

Obviously you can see this is different then what I was expecting it to read, so I did some math again. First making sure my original numbers where accurate and I didn't human error. Then I did the 4 hole slide calculations on 400 again to make sure I didn't mess that up. So I go back and do the 4 hole calculations as if it was 500 per hole, again came up with the wrong numbers. So I picked the number directly between the two and did the calculations on a 450 per hole slide. That math came out really close to what the cat scale told me my weights where on each axle group. So, unless you guys see something I missed... I am going to be assuming from now on 450 per hole on Prime trailers. And hopefully this little adventure will help others with their tandems slide that use Prime trailers.

Nothing is set in stone. Variables will be each trailer is different, each load is different, different manufacturers of the trailer, different tires, fuel level, geographic location, etc. It can be 250 to 500 lbs increments for each hole. This is something you will need to establish over time and by keeping records of individual loads and the trailers. One thing for sure is that if you weigh at a CAT Scale , it will be accurate.

Oh trust me, I'm well aware of the fact that that the actual tandem position is dependent upon how the trailer is loaded at the shipper. I've had to get loads reworked already because I just couldn't make them legal. What I am trying to establish is a good point of reference number that works for guestimating how many holes you need to slide to balance after the first weight so you can avoid spending time sliding and reweighting several times to get it right. Obviously some of this comes down to experience, but finding that sweet spot number wise makes a world of difference for us rookie drivers as far as managing our time wisely so we don't spend our whole 14 hours to drive 9 hours.

Definitely one of the myriad of “things to figure out” for drivers, especially in the first year. It sure is a lot off stuff, isn’t it?

Most certainly is, I like to look at things as a rookie as everything is my fault. Helps to try and keep myself centered and keep my learning. Also keeps me from being one of those arrogant(yet ignorant) truckers that blames everything on someone else including his fleet manager.

When I was there, it was generally said to be close to 500 per hole. Just remember that the newer trailers may be a little different in weight distribution then the older ones. That being said, I think you will find the sweet spot closer to about 350. This is what I planned on, and it generally worked in my favor.

Hope this helps, and best of luck to you figuring it out.

Just curious, what trucks do you guys drive? I'm currently in a 2017 Pete, so I have the awefully useful(well it is more useful now that I try and get used to it) suspension load gauge. I am somewhat sarcastic about this because I got to use the right weight gauge Freightliners have and it kinda spoiled me a bit. It's so much easier to try and balance out the load when you know the weight on your drives rather then trying to guess based on the psi on your suspension. For instance I know truck and trailer for me empty weighs in at around 36,000 with 11,400 on the steers. So if I know the weight of the load I can balance fairly easily with right weight, the suspension load gauge on peterbilts takes a bit more getting used to. It's not as easy to math it out, although you can with constant use start to figure out the roughly correct psi value you want for different weight loads to be balanced out.

I drove an 07 Freightliner up until mid-February.

My profile picture is what I have. It's a 2020 Cascadia. The bad thing is Swift got rid of the gauge for the drives, so I have no idea what it is until I scale. The positive, is I'm on a dedicated route , whose loads are usually light retail merchandise. Our heaviest load was 37k.

Sorry to hear that Scotty, it sucks when we lose tools that make our jobs easier.