Trailer break away cable

[John Kennett]

Originally Posted by nik

I can see the advantage of automatically applying thr brakes in the event of a disengagement, but if it also separates from the towing vehicle cannot be right.

This is how it's designed to work so someone obviously thinks it's right!

The reasoning is that you're better off with a stationary trailer not attached to you car instead of dragging it along by a bit of wire . . .

John

[Suzuki416]

I'll be selfish here and say that I have no intention of ever fitting a cable to my unbraked 2 wheel trailer..

The reason.
I had a wheel come off the trailer 1 week after I bought it on the way home from a day out at Cristchurch, Dorset. I had just driven 120 miles at 60-70 mph & was 100 yards from my house. I turned a bend (@10mph) & the wheel overtook me!
As I was going slowly the trailer just dug in on 1 side.

If this had happened just 2 minutes before I would have been doing 60-70 & there is no doubt in my mind that the vehicle would have been flipped.
Imagine now 2 vehicles barrel rolling along a 3 lane dual carriageway at 60mph!

I've been there & done that but that's another story!!

In my mind better to have 1 vehicle flip than 2.. & rather the trailer than the car.
Again this only really applies to 2 wheel unbraked trailers. If I had a 4 wheel braked trailer I would fit a breakaway cable but this would only be strong enough to activate the trailer brakes NOT to keep me attached to it.

Pete

[Headhunter]

Suzuki Pete
Quote
"I had a wheel come off the trailer 1 week after I bought it on the way home from a day out at Cristchurch, Dorset. I had just driven 120 miles at 60-70 mph & was 100 yards from my house. I turned a bend (@10mph) & the wheel overtook me!
As I was going slowly the trailer just dug in on 1 side.

If this had happened just 2 minutes before I would have been doing 60-70 & there is no doubt in my mind that the vehicle would have been flipped.
Imagine now 2 vehicles barrel rolling along a 3 lane dual carriageway at 60mph!"

Pete

If your trailer wheel came off at 60mph on a dual carriageway would the trailer separate from the hitch regardless of whether or not there was a cable backup?

John

[Mike B]

Again sadly from experience (Am I really that unlucky !).

Sometime ago we lost a wheel from a caravan doing roughly 60 mph. All happened very quickly. Luckly at the time we were in convoy with radio comms. The first we knew about it was a call from the person behind calmly suggesting we stop ! Once the wheel had separated, the caravan continued to run for some time on one wheel before the the rim came into contact with the road.

Luckily this did not cause the unit to flip but could easily have done so. Had it flipped im reasonably confident that the hitch would not have separated and flipped the car as well. Hence the use of a break away in this situation would not have much use or negative impact.

In my opinion if this was an un-braked trailer and a back up connection chain was used, if the force was sufficent for the hitch to fail or the tow ball to break I'm sure the chances are the back up would break too.

[nik]

This is how it's designed to work so someone obviously thinks it's right!

I have always been confident about the purpose of the wire loop for unbraked trailers, that is to prevent separation in the event of the hitch failing or not being put on properly.
It was braked trailers I was puzzled about. It seems the idea is to separate the trailer from towing vehicle and apply the brakes, so that the trailer will not shunt the towing vehicle and push it off the road. And it seems that they are usually quite stable when coasting on their own.
But all this is academic in the event of a wheel falling off or a puncture.
Nick.

[Headhunter]

Originally Posted by nik

It was braked trailers I was puzzled about.

Nick
I suspect it's the critical mass that is the issue with braked trailers.

Unbraked up to 750kg or 50% of the tow car.

My car has a towing capacity of 2000kg vs a vehicle weight of 1660kg

I would not tow a trailer weighing above the car weight, imagine the tail wagging the dog!

When I had a Landcruser it weighed 2500kgs and was rated to tow 3500kgs.
Imagine that lot if the coupling detached (yet the trailer was still attached to the tow by a wire or chain) with the trailer brakes now inoperative because the over run brake mechanism depends on the hitch being coupled correctly.

The reason for a breakaway cable is to apply the trailer brakes ASAP following unintentional uncoupling, leaving the towing vehicle to it's own devices.

With an unbraked trailer the towing vehicle is the only means of any attempt to control stopping the trailer should it become unattached.
Hence the weight limit on unbraked trailers and the strong wire/chain to prevent runaway.

Just thinking about the possible scenarios is scary enough for me so I hope I am never subjected to such an event.

John

[woot]

I may have misunderstood, maybe the loop that was fixed to my unbraked trailer is not a breakaway but in fact a strong loop capable of retaining the trailer in the event of the ball unhitching. In this case I may need to fabricate a new bracket to allow fitment of the loop and the hitchlock. That said from the arguments put forward I can't decide whether I would prefer it to be attached or not. Conclusion - the loop was on there when I bought it so I should put it back on or I may have some awkward questions to answer if I have an incident and the accident is investigated.

[chris jh]

Previous posts refer to two totally seperate types of cable:
Secondary Couplings: (Usually strong cable) Legally required on unbraked trailers manufactured/first used after specific date, as a means of retaining trailer to tow vehicle in the event of unintentional uncoupling.
Breakaway Cable:Legally required (weight specifc/date of manufacture specific) on braked trailers, and as previously stated to remotely operate trailer brakes in the the event of a de-coupling.
Secondary couplings can also be fitted to braked trailers, but would be likely to hinder the operation of the breakaway cable. Additionally, with a 'heavier' braked trailer a real risk of loss of control is likely if a secondary cable is fitted.
If anybody really needs the relevant weights/ relevant date of trailer manufacture I'll look them up and post. They are only complicated because they are spread across successive amendments to the Road Vehicles (Con and Use) regs