How far to slide tandems?

Let's see . . . if I remember correctly, 4" spaced holes on a trailer means 1 hole = 250 lbs. 6" hole spacing = about 500 lbs. Fifth wheel on every truck I've ever run is about 250 lbs - but I very rarely have had to slide my fifth wheel.

 

Can we give this thread it's last rights yet?

 

I hope you have found the answer you were looking for on how much weight per hole on sliding trailer tandoms. Here is an easy solution to your problem. There is usually a 100 pound shift per 1 inch of slide. Some holes on the trailers are 4 inchs on center. Some manyfacturers have their holes at 5 inchs on center. this is why there is the 400 to 500 pounds per notch. 4 inch centers will give you a 400 pound weight shift while the 5 inch holes will give you a 500 pound shift.

 

What I used to do in the absence of a dump valve was to lower the dollies and then go under the trailer. The valve that controls the suspension height has a metal arm with a rubber piece attached. I would bend the rubber part down so air is released from the bags. You can bend the metal rod, but don't recommend it.

I've done the same for getting under trailers that are too low and even one that was dropped on asphalt. But I would NOT recommend it for normal operation - only on occasions when the alternative is a lot of hard work.

Anyone else seen a pig trailer that had the tandems welded in place?

 

WOW am I confused! And I've been doing this for 32 years!

FIRST! DO NOT BELIEVE ANY SET WEIGHT FOR A HOLE!

I can tell you that the Utility reefers I pulled were 385 pounds a hole!
The great danes were 418 a hole so my next lesson is needed!

OK we know it all varies with the trailer and make of truck!

The BEST way to tell what each hole and slot equals in weight is to

1st LOAD THE TRAILER!

2nd: weight the unit!

3rd; figure out where you need to move weight and GUESS at an approxmiate guess say 350 on the trailer per hole and do the math for number of holes to slide. MARK the starting hole with chalk or a rock from the ground

4th: Slide to the hole prosition you "think" is the correct hole and lock it in and go weigh again. This is now going to cost you a whole dollar! This is a cost you can afford!

5th: Weigh and then with simple 5th grade math figure out how much weight you actually moved! If you will be hauling this trailer for long periods of time you now have an AVERAGE weight per hole. BUT yep there always is a BUT in simple things in trucking! The more holes you slide and depending on product and length of load in the trailer the "average" weight per hole can change either lighter or heavier! Never trust a "close" weight by not reweighing! Right now I believe it's still a whole dollar for the reweigh, then do it! Lot cheaper than paying for an over axle weight ticket!

This works for the 5th wheel also! But yes I'd stat with 500 a slot! A note to you L/P drivers. Tire and truck manufactures advise that you keep more weight on the steers. I've known some that would never put more than 10,000 but less on the steers and not figure out why the tires wore out so fast and why the thing "bounced" so much! I always keep my MY weight as high as I can on the steers and loaded weight at 11,000+. I keep the nose of the trailer on a FL and Pete almost even with the half flap, quarter flap or whatever you want to call the mudflap in front of the front drive. I never have to move it as when I'm fully loaded and full of fuel I'm usually close to 11,500+. My ride is smoother and I get good 175,000 miles mim on the steers as they don't "skip" from lighter weights and from "heavy on the drives" It keeps them on the ground with even pressure.

For those of you with the misconception that sliding the trailer tandems all the way to the rear makes the truck ride smoother go ahead and believe that! You're over loading the drives and rear suspension and bouncing the steers off the ground thinking you're now riding in a caddy!, That is not a good thing when riding in rain or frozen road conditions! Weight on the steers is a lot better! Plus you're not anywhere close to "bridge" when you need to be and turning in truck stops and cities it is just a lot harder to make turns and to back up! Shorten it up and balance the weights for a smoother ride! Just watch the swing out at the rear!

Now the fuel problem noted way up close to the front of the thread.

Diesel weighs 7.3 pounds per gallon for "regular" diesel. I've never checked the weights and measures site for bio diesel or other heavy fuels (meaning with more additives added) as I don't buy bio or other fuel unless the company tells me to do so. I use the 7.3 and I don't round the figure out as I just might need that .7 tenths of a gallon to get to a fuel stop when I can only put 50 pounds in the truck got me on this?

Lets do one more lesson!

New truck? New company and new every thing? Ready?

You're hooked to your new company and have your keys in hand and are about ready to go for a load. Is the truck fueled? NO? GOOD! Will the company let you fuel close by or in the yard? Is there a scale there? Yes?! GREAT! if not then go ahead and fuel and hit the road! We'll cover this when you need fuel after loading.

OK you're down the road and you have your load. The first thing is to do the above so you know the amounts of your holes, sounds almost kinky don't it?" Yeah, age messes with your brain!

You're now going to pull some of your own money out of your pocket or add to the first weight ticket as a "reweigh" ticket but will keep these for your own tax files.
You've weighed the truck and you have the weights where you want them but you need to know a few more things.

The first is, does that fuel gauge tell you the truth? Is it 1/2 MT or full? Is it on MT and you're guessing? Is the needle close to 1/8 MT or lower?

Does this truck have sending units on both tanks or on one? Look at the top of the tank. See the round part with two poles/screws sticking up with 2 wires? Thats the sending unit, go to the other tank. Is there one there? NO or yes it doesn't matter except for the single sending unit. Look at the fuel gauge. Hopefully it's below 1/8 and into the yellow if the gauge is so marked or almost to the MT mark.

Look into the tank with the sending unit with a flash light NOT A LIGHTER! Hot diesel fumes explode like gas fumes! And yes there IS a You Tube video of a driver doing exactly that! Yep, thinned out the gene pool on that one he did he did!

OK you've looked, now first fill the tank with the unit on it all the way to the top where you always plan to fill when doing a top off. Note the gallons you put in and then go to the other side and fill it and note the gallons again.

Now you know how many gallons the truck will take from that spot on the gauge. I forgot to tell you that I carry a metal ink marking pen that I put a tiny dot on the gauge to show where it was and it'll be my mark until I get a lower amount of fuel in the tank. This will now tell you how many gallons you have left in the tank in case you need to run with less fuel for more freight!

Anyway, you're now full of fuel. Get back on the scales and guess what?

You now know that putting 175 or whatever gallons of fuel in the truck you know how many pounds you just put on steers and drives! If for some reason you're at gross weight or real close to it you can decide if you want to put more weight on the steers or live with it for now!

A little math will tell you with how many gallons which axle will get how much weight!

I didn't give you a reason for the needing to know the fuel/weight ratio and the "spot on the gauge" deal did I? the spot on the gauge is for if you're in a tight weight load. you're in the middle of BFE and you're at your "spot" on the gauge. So you have I'll say 62 gallons of USEABLE fuel. With the 62 gallon figure you now know how much father you can go before running out. Just don't push that like I did once! That was a $135 service call! A hard lesson BUT I did find out exactly how many gallons i could put the tank!

Remember the more you know about that truck the better! The weights are one of the most important! The more weight you can haul sometimes counts into the money you make.

When figuring out your fuel do it on the 7.3 pound figure and not the 8 pound as that .7 tents might be needed down the road and they do add up in full gallons also!

I think we're done here! LOL

 

Alright I have more weight questions. I haven't been doing this for very long so bear with me. I have run in CA a decent amount, so I understand that if your tandems are at the 40' mark and you're overweight on them, then you're boned since you can't scoot them back anymore. But say you're in a state with no bridge law - where's the optimum position to have your tandems at? Where should you generally start with them set when you weigh to see if you need to move them at all? Should your objective be to get the drives and the tandems equally balanced? I get the drawback of having them all the way forward (you might take something out with the swing) and having them all the way back (you're liable to run something over on a turn). Do you basically just guess somewhere in the middle and go from there?

 

RTO, I'm feeling pretty good right now after reading your entire post. I understood every thing you posted. I had plenty of opportunity to "juggle" the weight numbers to know how much, one way or another to slide the tandems on a loaded trailer, while I was out doing the mentoring deal. I know I'll have to learn what the "tare" weight of my truck with X number of gallons in the tanks will be and with an empty trailer. The only question I have is, "empty" trailers weigh differing amounts. Is the "spread" in 53' trailer weights (empty) so significant that it discounts a predetermined "tare weight"?

 

Generally you're looking to have legal weights on both sets of tires, but... it does affect fuel economy. The trailer tandems are the most sensitive set as far as fuel economy is concerned, so its best to load the drives a little more than the tandems. I've been putting about 1000 to 2000lbs more on my drives with our trailers equipped with duals, and about 2000 to 3000lbs more on the drives when I have a trailer with wide singles. Seems to work. Oh yeah, if its easy to slide your tandems, run them all the way forward when you're deadheading. Otherwise do the best you can, and get the bridge law or maximum legal weights taken care of.

It can. My carrier has been cutting the weight of our new trailers as much as they can... they've pulled about 3500lbs out of them. So yeah, it can be significant.

 

The only definite answer on how far to slide tandems is 10'-2" apart and never touch them again!