Tongue weight in Europe is around 7%
I know I am going to get some super experienced folks in the U.S. criticizing tongue/hitch weights being less than 10%, but let's discuss this. It seems the approach in the U.K. and Europe is to atte...
Forum Discussion
rvtrailerpuller wrote:I would suggest just one change to your statement -- the load should be concentrated as close as possible to the trailer's CG, rather than the axle.
---The goal, again, is to concentrate the load just as close to the axle as possible and just forward of it such that the tongue weight ends up in the 5% to 7% range.---
The optimum distance from the CG to the axle is determined by:
1) the distance from the ball coupler to the trailer's axle(s),
2) the trailer's polar (yaw) moment of inertia, and
3) the trailer's mass
Tongue weight percentage is a measure of the ratio of distance from TT's axles to TT's center of gravity divided by the distance from TT's axles to the ball coupler.
The ratio is important because it is one of the factors which determine how much lateral force the TT might exert on the ball.
For given TT mass, polar moment of inertia, dimensions, and application of lateral force on the TT, there is an optimum value of tongue weight percentage which will minimize the lateral force which the TT imposes on the ball coupler.
When a right-directed lateral force is applied to a TT at a point behind the CG, two things happen:
1) the TT's CG begins to accelerate toward the right, and
2) the TT begins a counter-clockwise (when viewed from above) yaw acceleration about the CG.
The right-directed acceleration of the CG causes the ball coupler to tend to move to the right.
The CCW yaw acceleration of the TT about the CG causes the ball coupler to tend to move to the left.
With the optimum TW%, the right-directed acceleration of the coupler will be equal to the left-directed acceleration, and there will be little or no lateral force imposed on the ball.
If you want to dig deeper into how tongue weight percentage is related to lateral force imposed on the ball, an attempt to explain the process is given in this post.
My first TT was an ABI Award made in Canada and based on a British design. It was 27' long, had a loaded weight of 5000#, a loaded tongue weight of 500#, and towed very nicely with a 1994 Ford Explorer using a Drawtite WDH and a single friction sway bar.
Ron
