Help me understand tongue weight (1 Viewer)

[Romer]

I am modifying my Kamper putting some more weigth ahead of the axles.

If I add 100 lbs 3/4 of the way between the axle and hitch (closer to hitch), how much does this increase the tongue weight?

 

[bowyer2002]

Simple way would be to stand on a scale & hold the tounge while being weighed.
THEN load the tounge as you're proposing and weigh again.
My understanding of tounge weight is how many lbs of force are applied to the ball/hitch from the tounge at towing height - this is a static weight measurement.
Please correct me if I am wrong!

 

[Romer]

Simple way would be to stand on a scale & hold the tounge while being weighed.
THEN load the tounge as you're proposing and weigh again.
My understanding of tounge weight is how many lbs of force are applied to the ball/hitch from the tounge at towing height - this is a static weight measurement.
Please correct me if I am wrong!

Thanks, that part I understood. Found some sites link from expo that discuss first finding your center of gravity via several equations and determing your draw and type of hitch and claculating that out to determine the effect of placement (location and weight) on the tongue weight.

Or I could measure the tongue weight, add the same approx weight and re-weigh. It's not a one for one increase.

 

[bowyer2002]

What is the distance from your axle (fulcrum) to the hitching point?

 

[Romer]

What is the distance from your axle (fulcrum) to the hitching point?

The gross weight is 3500 lbs

The water tank stradles the axle

I am removing about 25 lbs of fixture meant to hold an outboard boat motore

I am adding a steel box and a second 70lb battery.

Trying to decide between the smaller 25 lb box or the larger 55lb box. But the larger box will also hold more gear so add another 20 lbs

Box is to hold dual batteries

So the real question is if I install about 120 lbs 36-46 inches back from the tow ball, how much of an impact on tongue weight is that?

 

[Jbissell]

Formula: force * distance - force * distance = 0 (forces cancel equally)

10 - 3.2 = 6.8

X * (10) - 120 * (6.8) = 0

-> (solve for X, the unknown force)

X * 10 = 816

X = 816 / 10

X = 81.6 lbs of added weight on the tongue.


J.Biz

 

[Romer]

Thanks, I appreciate it. Just what I wanted to know.

I am going to use a smaller box that just holds two batteries, so really just adding a battery as the box weighs about the same as the outboard motor mounts I just cut off

70 lb battery would add about 46lbs of tongue weight. That shouldn't be an issue.

Thanks again

Formula: force * distance - force * distance = 0 (forces cancel equally)

10 - 3.2 = 6.8

X * (10) - 120 * (6.8) = 0

-> (solve for X, the unknown force)

X * 10 = 816

X = 816 / 10

X = 81.6 lbs of added weight on the tongue.


J.Biz

 

[Jbissell]

No problem! Glad I was able to help.

 

[spressomon]

Ken,

Have you actually weighed your KK? FWIW: James has weighed his fully loaded and its generally in the 2,500-2,600lb range with water and fuel but sans the extra canvas walls.

Interesting thread BTW. Thanks for the formula Jbissell!

Dan

 

[titanpat57]

I think I would be tempted to put them in the storage area under the bed...closer to the axle. Is that where you just put the heater? One of the things you have to careful of is to provide a battery cover so nothing could come in contact with the terminals. Are you using AGL or lead acid?

It's hard to tell how big the steel is for the frame, but if was designed to hold a boat motor (what size?) then maybe from a weight standpoint it would be ok.

 

[Romer]

Ken,

Have you actually weighed your KK? FWIW: James has weighed his fully loaded and its generally in the 2,500-2,600lb range with water and fuel but sans the extra canvas walls.

Interesting thread BTW. Thanks for the formula Jbissell!

Dan

I haven't weighed it, the tag says 1500kg and I think thats 3500 lbs GWR. The weight you listed seems more realistic

I think I would be tempted to put them in the storage area under the bed...closer to the axle. Is that where you just put the heater? One of the things you have to careful of is to provide a battery cover so nothing could come in contact with the terminals. Are you using AGL or lead acid?

It's hard to tell how big the steel is for the frame, but if was designed to hold a boat motor (what size?) then maybe from a weight standpoint it would be ok.

I am using AGM batteries. Not sure what size motoe, but the brackets I just cut off were pretty beefy.

 

[45Kevin]

You know that by adding weight aft of the axle you can counter-balance some or all of the added tongue weight.

Looks likes a nice trailer.

 

[Jbissell]

Interesting thread BTW. Thanks for the formula Jbissell!

Dan

Not a problem. Glad to know one of my engineering classes finally came in useful...

 

[Ebag333]

Have you actually weighed your KK? FWIW: James has weighed his fully loaded and its generally in the 2,500-2,600lb range with water and fuel but sans the extra canvas walls.

X = 81.6 lbs of added weight on the tongue.

If the weight is only 2.5k lbs and you're adding 80 lbs of weight, that's actually quite a bit, over 3% of the total trailer weight. From everything I've read, you want the tongue weight to be around 10% of the total weight.

I would weigh your trailer, then weigh the tongue and see what the tongue weight is. If you're going to be way over that 10%, you might want to look at other options.