[BRG75]

Reversing a trailer with precision, does come with practice, and an understanding of the principles involved.

If you are anywhere near touching your trailer, with your bumper, then you have gone well past the point of being in control.

Like many things, reading about what to do can be more confusing than observing the geometry involved, in practise. A simple method is to use a model car and trailer, and “reverse” it on a table top. Nearly as good, is two model cars, lorries, or whatever; two blobs of blue tack and two paper clips, suitably bent.
The second car can be reversed, as if it was a trailer.

You will quickly see the point, or angle, where the trailer stops moving backwards, under control.
After this point, the car is reversing into the trailer (and trying to push it sideways) rather than properly reversing it.

The point is actually called “the follow through”, and it is where you change over from turning your steering wheel to the left (to turn the trailer right) to turning the steering wheel right (to continue turning the trailer to the right)

There are other factors involved.

1. The longer the distance from the tow ball to the trailer wheels, the easier it is to reverse the trailer.
This is because the follow through comes much later, or if you like, at a greater angle.
The hardest trailer to reverse is a 3 or 4 ft long box trailer, simply because you often can’t see it, and the follow through point is almost immediately after you start moving.

2. The distance between the towing cars’ rear axle, and its’ tow ball.

3. The wheel base of the towing car also has an effect, but not of any great significance.

As to a device to assist reverse towing, I don’t know if there are any on the market today, but years ago I couldn’t find any (pre internet)

Although I never did assemble the following, so not tested, I think it might work.

Essentially:-
Two short chains, permanently attached to the front corners of the trailer.
With a removable shackle, or possibly a large spring hook, connect them to two eyes, that are fastened as far as possible from the towing ball, directly onto the tow bar.
The length of the chain, stretched tight, determined by trial and error, to stop the trailer from pivoting on the ball; just before the “follow through angle”

All of this would need to be well engineered, as the forces involved are going to be considerable.

My apologies if this is already a recognised method,

Regards

Mike