Trailer Axle Position & Tongue Weight

Every load on a trailer is carried partly by the axle and partly by the coupler, and the split is decided by one distance: how far the combined centre of gravity sits in front of the axle. Taking moments about the axle, the tongue carries Σ Wᵢ(ℓ − xᵢ) ÷ ℓ. Turn it around and the axle position for a target tongue share is ℓ = Σ Wᵢxᵢ ÷ (W − T), which is the question people usually have. The two loads always add up to the total: weight taken off the tongue does not disappear, it moves onto the axle.

A trailer with its centre of gravity behind the axle is directionally unstable. Once it starts to yaw, the sideways force acts behind the pivot and pushes it further, so the oscillation grows instead of damping — and speed makes it worse, not better. That much is geometry rather than opinion. The percentage to aim for is not: it comes from your trailer maker and your towing handbook, so it is an input here with a band you set, and the page reports where you sit against your own target rather than against a number it made up. Too much tongue weight is the safer error, but it lifts the tow vehicle’s front axle and takes steering and braking with it.

Static, level, in a straight line, with nothing sliding. No suspension, no weight-distributing hitch (which moves load back onto the tow vehicle’s front axle, changing every number here), no side-to-side balance, no aerodynamics and no braking. Coupler ratings, axle ratings, gross weights and every legal limit are your inputs from the plate and the handbook — none is stored, because the ones that govern you are on your trailer and in your local rules. Weigh the tongue rather than trusting an arithmetic model of a trailer you have not measured. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.