Lowboy weight adjustment question?

JBGASH · Oct 12, 2012

I have a 25 ton lowboy that when loaded we are 33,580# on the tandems on the trailer axles, the max in Missouri is 34,000# With that said, it needs a new oak floor, and would like to put 2 1/2" oak instead of the 2" that is there now. The truck has a sliding fith wheel. The question is: when you slide the fith wheel forward will it take weight off of the lowboy axles and shift it onto the road tractor? Note: The excavator that is hauled on it is parked all the way forward on the lowboy.

lumberjack · Oct 12, 2012

Sliding it back takes weight off.

brianbulldozer · Oct 12, 2012

JBGASH said:
I have a 25 ton lowboy that when loaded we are 33,580# on the tandems on the trailer axles, the max in Missouri is 34,000# With that said, it needs a new oak floor, and would like to put 2 1/2" oak instead of the 2" that is there now. The truck has a sliding fith wheel. The question is: when you slide the fith wheel forward will it take weight off of the lowboy axles and shift it onto the road tractor? Note: The excavator that is hauled on it is parked all the way forward on the lowboy.

The position of the fifth wheel only changes the weight distribution between the axles on the tractor. The amount of weight applied to the fifth wheel by the trailer and excavator is the same regardless of where on the truck frame the fifth wheel is located. I have the same problem with a fifth wheel tilt deck trailer. The trailer gets around town great, but a little more wheel base would sure help.

Knocker of rock · Oct 12, 2012

brianbulldozer said:
The position of the fifth wheel only changes the weight distribution between the axles on the tractor. The amount of weight applied to the fifth wheel by the trailer and excavator is the same regardless of where on the truck frame the fifth wheel is located. I have the same problem with a fifth wheel tilt deck trailer. The trailer gets around town great, but a little more wheel base would sure help.

I had to read the OP several times, but you are completely correct

lumberjack · Oct 12, 2012

Indeed he is, I wasn't thinking straight!

JDOFMEMI · Oct 12, 2012

So does the extra 1/2" of Oak weight more than 800#? Th etrailer will only carry roughly 1/2 of the weight of the deck, so you could add that much and still be legal. You could also look into moving the kingpin of the trailer back a few inches, if there is enough clearance, but that is a big project.

Moving the 5th wheel will only affect the weight of the truck axles, not of the trailer.

JBlackwell · Oct 12, 2012

I think you would be OK. If you need comfort room and can move the load 6" further forward that will take an extra 300# off the trailer and put it on the truck.

Justin

JBGASH · Oct 12, 2012

I am unsure of how much more weight the additional 1/2" of oak will add. I had the oak sawed and did not even think about the weight issue until I picked it up. A mistake on my part. I am going to lay the oak on the trailer and not fasten it down, load the excavator and then go weigh the rig on a Cat scale. We are rebuilding the suspension & repainting the lowboy why it is stripped down so in a few days I will post the outcome of it. Thanks for the posts to all.

JBGASH · Oct 12, 2012

JDOFMEMI said:
So does the extra 1/2" of Oak weight more than 800#? Th etrailer will only carry roughly 1/2 of the weight of the deck, so you could add that much and still be legal. You could also look into moving the kingpin of the trailer back a few inches, if there is enough clearance, but that is a big project.

Moving the 5th wheel will only affect the weight of the truck axles, not of the trailer.

Not sure how additional weight the oak will put on it, but I do have plenty of room to move the kingpin back. It is showing wear anyway.

rigandig · Oct 13, 2012

The new oak will be a bit heavier just by reason of thickness alone, and add to that if it is still "green" some more weight for the moisture content. The only thing in relation to the front coupling area that will change the weight distribution would be to move the kingpin back ,if you have another kingpin hole built into the gooseneck. Simply sliding the 5th wheel forward will only accomplish what the others have said above. Somehow you will need to move your c/g (center of gravity) of the load forward.

rigandig · Oct 13, 2012

Concerning the weight of the Oak. Fresh cut Oak weighs 12 lbs per bd foot in log form. After sawing that is reduced to 1/2 of that. Once it is dried you can reduce that some more, but not knowing the moisture content of what you have atm, all is speculation. Going from a 20% to 10% moisture content will reduce the weight by 30%. So, to speculate, your new boards, when dried would be approximately 1 to2 lbs more per boards foot than your old ones. The sure way is what you plan already, place the boards, load the machine, and go weigh it.

JBGASH · Oct 13, 2012

rigandig said:
Concerning the weight of the Oak. Fresh cut Oak weighs 12 lbs per bd foot in log form. After sawing that is reduced to 1/2 of that. Once it is dried you can reduce that some more, but not knowing the moisture content of what you have atm, all is speculation. Going from a 20% to 10% moisture content will reduce the weight by 30%. So, to speculate, your new boards, when dried would be approximately 1 to2 lbs more per boards foot than your old ones. The sure way is what you plan already, place the boards, load the machine, and go weigh it.

Thank you riganddig, I had no idea of the weight of the oak. A good guess would be around 4# pbf after it dries form what you are saying, assuming it has 10% moisture?

Birken Vogt · Oct 14, 2012

This makes me think of a question, has anybody gotten a ticket for overweight because the weight of water some boards might have soaked up if it rained on an otherwise legal load?

kylefitzy · Oct 14, 2012

In Missouri on non-interstate highways the maxim weight on a tandem is 36,000 as long as you have at least 40" spacing between axles. You can only have 34,000 on the tandems if you are on the interstate because federal laws, not state laws, apply then.

I personally have left the yard at 80,000 even and hit rain and crossed the state scales at 80,800 in a pounding rain storm and got the green light. I would say it depends on the officers mood.

Knocker of rock · Oct 14, 2012

My friend was stopped on his boom-truck and was 200#s over on the rear. The officer didn't care, said he was concerned with heavt haulers and dumps which could be several thousand over. Told my friend to try to shift some blocks around, and maybe come up with a new spot for the spare tire.

The end

06Pete · Oct 14, 2012

Around here you are are aloud 1000# over before a ticket but once a 1001# the ticket starts at your legal weight. It always depends on the officers mood as they can find something wrong if they want to write a ticket.

JBGASH · Oct 14, 2012

kylefitzy said:
In Missouri on non-interstate highways the maxim weight on a tandem is 36,000 as long as you have at least 40" spacing between axles. You can only have 34,000 on the tandems if you are on the interstate because federal laws, not state laws, apply then.

I personally have left the yard at 80,000 even and hit rain and crossed the state scales at 80,800 in a pounding rain storm and got the green light. I would say it depends on the officers mood.

I see you are from Kansas City, I have to cross the scale at Odessa quite often so I was trying to keep it legal to avoid any issues.

Lowboy weight adjustment question?

JBGASH

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lumberjack

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brianbulldozer

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Knocker of rock

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lumberjack

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JDOFMEMI

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JBlackwell

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JBGASH

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JBGASH

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rigandig

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rigandig

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JBGASH

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Birken Vogt

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kylefitzy

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Knocker of rock

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06Pete

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JBGASH

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