Formula for calculating rear axle load related to tongue weight.

[TakeItEasy]

I ran across a formula for calculating the amount of weight a trailer tongue puts on the rear axle and takes off the front axle. The formula assumes no weight distribution. I was wondering if anyone knows how accurate the formula is. It could be checked using cat scales but it would take a couple weighs and some time.

Rear axle load = tongue weight * ((wheelbase + rear overhang) / rear overhang)

Front axle load = tongue weight - rear axle load calculates above

[TakeItEasy]

I checked the formula using a ruler, pencils to represent front and rear tires and a postage scale. The pencils where placed at the appropriate distances on the ruler to represent a scaled version of my 3170.

When I added quarters to the end of the ruler the result was as the formula predicted. In my case each 1 pound on the hitch add 1.6 pounds to the rear axle and takes 0.6 pounds off the front axle.

[thebrakeman]

Yes, it's correct.

[TakeItEasy]

Thanks for confirming thebrakeman. I was surprised how much weight a tow dolly added to the rear axle of my class C. That is when I went looking for the formula. I figured some of the other people running trailers without weight distribution could benefit front the formula.