Axle Position Calculator

By calculating the moments created by different loads about the hitch we can calculate the correct axle position for a specified tongue load.  Although the calculator above only takes into 3 primary loads (the trailer frame itself, the tiny house load and any point load applied to the drawbar), you can manually calculate the axle position for any number of given loads at a certain distance using the equation for D(a) below.

Manual Equations:

D(a) = (F(th) x D(th)) + (F(f) x D(f)) + (F(d) x D(d)) + …(F(l1) x D(l1)) + (F(l2) x D(l2))…)/F(a)

F(t) = (tongue load %)/100 x (F(th) + F(f) + F(d) +…F(l1) + F(l2)…)

F(a) = (100-tongue load %)/100 x (F(th) + F(f) + F(d) +…F(l1) + F(l2)...)

Definitions:

F(a) = Load on axle set

F(th) = Load of Tiny House.  Although this is the hardest to calculate, if your tiny house is built with keeping weight balanced on the trailer deck, you can assume the load acts through the trailer deck center.  Any heavy point loads that may upset the balance can be manually added and calculated as point loads.

F(f) = Load of the trailer frame.  This will act forward of the center of the deck due to the weight of the drawbar

F(d) = Point Load on drawbar.  This could be water tank, battery bank etc.

** For multiple axles sets the axle center is assumed to be in the center of the axle set. 

To learn more about axle position and trailer loads read the blog post on Trailer Axle Position.