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Thread: Front axle weight

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    Front axle weight

    Took my brand new 310 GK and 3500 ram dually to i the cat scales today: I use an Anderson hitch and with the trailer on the front axle weight was 140 pounds less than the truck with no trailer. I think this is because I have the coupling block in front of the fifth pin. Do I need to be concerned do you think? I like the Anderson. Lots of turning space so donít want to rotate the coupler if not needed
    Paul,Judy and Ember
    2021 310gk
    2019 ram 3500 mega cab dually diesel
    Andersen hitch

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    Site Team traveldawg's Avatar
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    It sounds to me that because of the way you oriented the hitch you took weight off the front wheels to allow more turning room to clear the cab. It sounds like the pin of the fifth wheel is now behind the rear axel thus lowering the weight on the front axel.

    I think traditionally the pin of the fifth wheel should be either over the rear axel or slightly forward. This results in proper weight distribution on the tow vehicle.

    If your set up is as I expect then the more you load the 5th wheel, the lighter your front end is going to get on your truck.

    Personally I prefer to have the 5th wheel pin over or forward of the rear axel.

    I have no idea if the way you are set up needs to be a concern or not. I expect others will chime in soon.
    Larry
    2018 F350 SRW SB - AirLift 5000 w/Wireless One; ForScan; 37gal RDS Fuel Tank; Demco Hikacker
    2019 310GK-R - Sailuns; MorRyde SRE4000; Disc Brakes (StopYourTrailer.com); Electric Cord Reel


  3. #3
    Site Sponsor Jerryr's Avatar
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    NOT A PROBLEM! Itís not because of how you mounted the Andersen coupler.

    If you look closely at the Andersen hitch the Andersen ball is 4Ē BEHIND the truck bed goose ball. The truck bed goose ball is essentially directly over the rear axle. So the force vector is applied on the Andersen ball which puts the force 4Ē behind the truck axle.
    Jerry & Linda
    With Cleopatra our Jack Russell & and JR our Amazon Parrot
    2017 Reflection 337RLS, Build Date 01/2017, Titan Disk Brakes, Goodyear G614s 235/85/16 G Rated tires
    2020 F-350 Lariat Ultimate 4x4 PSD SRW Short Bed, 3483 lb Payload, Factory 5th Wheel Prep, Bedrug Bedliner, Andersen Ultimate II Aluminum 5th wheel hitch
    http://visitedstatesmap.com/image/FLGANCSCsm.jpg

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    Quote Originally Posted by Jerryr View Post
    NOT A PROBLEM! It’s not because of how you mounted the Andersen coupler.

    If you look closely at the Andersen hitch the Andersen ball is 4” BEHIND the truck bed goose ball. The truck bed goose ball is essentially directly over the rear axle. So the force vector is applied on the Andersen ball which puts the force 4” behind the truck axle.
    Yes the ball on the hitch is behind the axle and when I put the Cupler in front of the king pin it push it back even further on the back axle.So I know why it’s happening I just want to know if I should be concerned with weight coming off the front axle and how much could come off before I have a problem
    Paul,Judy and Ember
    2021 310gk
    2019 ram 3500 mega cab dually diesel
    Andersen hitch

  5. #5
    Site Sponsor Jerryr's Avatar
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    Quote Originally Posted by Kretzer View Post
    Yes the ball on the hitch is behind the axle and when I put the Cupler in front of the king pin it push it back even further on the back axle.So I know why it’s happening I just want to know if I should be concerned with weight coming off the front axle and how much could come off before I have a problem
    The physics of the force vector on the truck doesn’t change if the coupler is mounted in standard position or reverse position because the force is applied to the Andersen ball which is fixed in place. The fulcrum is the rear axle and the moment arm is the distance from the rear axle and the Andersen ball. That moment arm doesn’t change if you flip the coupler.

    The only thing that changes is the amount of force the trailer applies to the Andersen ball due to the moment arm changing in the trailer, between the coupler socket and the trailer wheels. Even that is very slight.

    Everyone with an Andersen hitch will lighten the weight on the front axle because the Andersen ball is behind the truck axle. Mine reduces the front axle weight by about 100 lbs. it’s nothing to worry about.

    The only way to reduce the effect is to move the hitch forward so the the Andersen ball is more forward.
    Jerry & Linda
    With Cleopatra our Jack Russell & and JR our Amazon Parrot
    2017 Reflection 337RLS, Build Date 01/2017, Titan Disk Brakes, Goodyear G614s 235/85/16 G Rated tires
    2020 F-350 Lariat Ultimate 4x4 PSD SRW Short Bed, 3483 lb Payload, Factory 5th Wheel Prep, Bedrug Bedliner, Andersen Ultimate II Aluminum 5th wheel hitch
    http://visitedstatesmap.com/image/FLGANCSCsm.jpg

  6. #6
    Setting Up Camp
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    Quote Originally Posted by Jerryr View Post
    The physics of the force vector on the truck doesn’t change if the coupler is mounted in standard position or reverse position because the force is applied to the Andersen ball which is fixed in place. The fulcrum is the rear axle and the moment arm is the distance from the rear axle and the Andersen ball. That moment arm doesn’t change if you flip the coupler.

    The only thing that changes is the amount of force the trailer applies to the Andersen ball due to the moment arm changing in the trailer, between the coupler socket and the trailer wheels. Even that is very slight.

    Everyone with an Andersen hitch will lighten the weight on the front axle because the Andersen ball is behind the truck axle. Mine reduces the front axle weight by about 100 lbs. it’s nothing to worry about.

    The only way to reduce the effect is to move the hitch forward so the the Andersen ball is more forward.
    Awesome thanks
    Your comments brought back my high school physics class LOL
    Paul,Judy and Ember
    2021 310gk
    2019 ram 3500 mega cab dually diesel
    Andersen hitch

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