Transitioning a Tractor from Tandem Loads to Heavy Haul

Luke905

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Apr 29, 2016
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I am trying to get some information about transitioning a regular tractor to haul heavy multi-axle loads in Ontario/Michigan.

Do I need to make any changes to make the tractor legal, for example changing the steer tires?
 
Make sure your IRP is valid for the weights you are going to gross. Also ensure the axles and tires are rated for the weights you are going to be handling.
 
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You will have to ensure that the axle weight ratings are designed for what the new gross weight will be. For example, is your steering axle rated at 12K, or 14K? Same for your drive axles, 44K or 48K? I certainly am not an expert, being merely a stupid load broker, but from my ancient experiencing in truck leasing, those are the items I would check first. Higher load rated tires might help, but the axle ratings I think, are the critical components.
 
Make sure your IFTA is valid for the weights you are going to gross. Also ensure the axles and tires are rated for the weights you are going to be handling.
IFTA? I think you mean IRP ... IFTA is just your fuel tax account and is not weight dependent. IRP is definitely weight dependent though.

As for the truck, 12's and 40's will be fine. Your trailer axles will pick up the extra weight. What I would be most concerned about is that 1) you have enough horsepower, 2) you have enough transmission, and 3) you have a heavy enough rear axle ratio.
A 375 HP DD13 with a 10 speed direct and 2.93:1 axle ratio will not pull 130,000 lbs gross for very long.
 
It is always the weakest component that gives up first. I remember an incident where it was the driveshaft not spec'd correctly that let go. Good point Michael, all that torque required to get a heavy load moving, has to be smoothly transferred to to the drive axles thru a properly spec'd differential.
 
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IFTA? I think you mean IRP ... IFTA is just your fuel tax account and is not weight dependent. IRP is definitely weight dependent though.

As for the truck, 12's and 40's will be fine. Your trailer axles will pick up the extra weight. What I would be most concerned about is that 1) you have enough horsepower, 2) you have enough transmission, and 3) you have a heavy enough rear axle ratio.
A 375 HP DD13 with a 10 speed direct and 2.93:1 axle ratio will not pull 130,000 lbs gross for very long.
Thank you for the correction, I was just doing my quaterly IFTA filing at the time...
 
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I haven't seen a double frame tractor in ages !!!
I suppose if you were pulling super loads, you would need a double frame, but that would be about it. The reality is there is no more vertical weight on the tractor for a 130,000 lb load than there is for a 80,000 lb load. There is however, a lot more fore and aft horizontal stress, and some additional lateral stress.
 
I was talking with my Penske rep (he actually knows his stuff) and he said double framed highway tractors are impossible to get he has tried for years and it all goes to severe duty.
 
Your axle and tire rating are what's most important. If you have 40K rearendstogether caught weighing over 40K. Places such as PQ and NY require your actual tire weight rating on permit applications.