Does the Tongue Weight of a Trailer Get Transferred to the Rear Axle of a Truck

Updated 05/03/2020 | Published 10/02/2015

Question:

If a tow ball weight is 280kg, how much load does this put on the rear axle and how much will it increase if i extend the tow ball distance from the axle? Is there a calculator for this?

asked by: Gary.

Expert Reply:

A trailer with 280kg (617 pounds) tongue weight would exert less than that weight on the actual rear axle of the tow vehicle. There isn't a calculator for this because you also have to take into account suspension components which transfer weight to the frame and only a portion of that gets transferred to the axle.

The best way to get a good estimate of how much weight is on the rear axle is to use a scale that can be placed just under the rear wheels. Then you could weigh the tow vehicle rear axle by itself and then weigh it again with the trailer connected. The difference would then be the weight applied from the trailer to the rear axle.

I am not sure where you would go for a scale like this locally but some big rig scales have multiple platforms that could handle this kind of test.

Moving the ball further from the tow vehicle will apply more leverage to the hitch and tow vehicle due to the increased distance but it would not add any more weight. the weight would be a little less.

expert reply by: Michael H

Stephen D.

4/29/2020

I have a 6100 lb trailer with a tongue weight of 800lbs the truck weighs 6000lbs with myself and full tank. Went back to scales today with trailer hooked up and truck weight was 6481, what happened to 800-481=319lbs of tongue weight??

Chris R.

5/1/2020

I'm not quite sure what you are asking. Where did you get that formula that you used for the tongue weight? As Michael mentioned above, there isn't a set formula or way to calculate exactly how much of the trailer's tongue weight will be transferred to the truck's ear axle, so any calculations done beforehand would just be a way to get a general estimate.

Stephen D.

5/1/2020

@ChrisR The tongue weight was measured by the RV dealer. I was told it was 800 lbs. I thought I would see that additional weight on my truck. I then weighed by truck again with trailer attached. The total of the two truck axles was 6481. I thought it would be at minimum 6800 plus the hitch weight. Thats where my confusion is. I

Chris R.

5/3/2020

I understand now. While it may not be exact, most of that tongue weight should be transferring over to the truck's weight when using a scale. It sounds like that 800 pound tongue weight the dealer gave you was maybe an estimate - this number will change depending on how you actually load the trailer (not just how much weight you add to it, but WHERE it's added). Actually weighing everything at a local scale like you did is the most accurate method you can use.