Thread: A Frame Towing

Easo

The problem with most "A" frames is that unless both vehicles are in a straight line on flat ground, there is tension in one arm of the "A" and they are impossible to un-couple. The solution to this is for one or preferably both arms to telescope then lock into position for towing. To uncouple the lock on the telescope mechanism is released and then the coupling on the towing vehicle can be released also.

I have been considering making a pair of "rock sliders" for my SIIB 130 that can be used as an emergency "A" frame. Each end would have Cat B ball joints from a tractor 3 point linkage and a coupling device to connect everything together.

Dana

Originally Posted by easo

I have seen a bloke towing a mazda 121. The 'A' frame could close away for storage. He used 2x concealed haymen Reece sockets in the front bumper of the 121, so he could pull out the tow balls to drive it. He had 3 tow balls all up, two on the 121 and the third 'well on the van'.

I fitted propshaft universals for the rear pivots on mine - does the same job I guess.

Originally Posted by slug_burner

There are two categories in the bulletins, one for GVM 4500 kg or less and for over the said GVM. Given the weight of an 80" the section we need to concern ourselves with is that for GVM > 4500 kg as max towed vehicle weight is 1000 kg for the GVM to be 4500 kg as well as comply with the 3.5 times weight ratio.

Unless I have missed it the RTA does notr require this 3.5 time weight ratio - only requires the towed vehicle is less than the towing capcity of the tow vehicle and towing gear (the brake test comes into play) - so in theory if all other conditions could be met - my Freelander with a 2 tonne capacity can tow a series 1 with a certified A Frame.

Diana - the RTA rules specifically forbid a driver/controller in the towed vehicle.

Cheers

Garry

Originally Posted by garrycol

<snip> ... Diana - the RTA rules specifically forbid a driver/controller in the towed vehicle.

Cheers

Garry

Thanks Garry

My research and discussions with the RTA were done a couple of years ago and the competent person was in there at that time, so this may be a new change in the regulations. It is probably a good change, however "emergency towing" using a rope or solid pole requires a driver in the towed vehicle. If an "A" Frame instead of the other two devices was being used for an emergency tow, it would be a reasonable excuse that a driver was in the towed vehicle.

Diana

The Australian Road Rules state:-

294(1) The driver of a motor vehicle must not tow another motor vehicle unless:
(a) either:
(i) the driver can control the movement of the towed vehicle; or
(ii) the brakes and steering of the towed vehicle are in working order and a person who is licensed to
drive the towed vehicle is sitting in the driver’s seat of the towed vehicle, and is in control of it’s brakes
and steering; and
(b) it is safe to tow the vehicle.

The statement in red above is what allows you to do away with the person in the towed vehicle while using an A frame.

On re-reading the RTA`requirements the towed vehicles brakes have to be able to be operated from the towing vehicle.

How would you rig such as setup given the towed vehicle already has a fuloly integrated system?? Is there an electric mechanisim that can operate the brake pedal or is there means of hacking into the hydraulics??

It is now getting to the stage that it would be easier to mod a big box trailer to carry the car.

Cheers

Garry

Garry,

I have not read it in detail. What paragraph makes you say that?

If you did have to be able to activate the brakes on the towed vehicle I would be looking at a solenoid/linear motor that could be attached to the master cylinder. Problems will start if you have power assisted brakes as there will be no vacuum on board the towed vehicle unless you make arrangements for it.

Other option would be an air ram onto the master cylinder off a compressor with a similar arangement to an air locker.

Depending on the towing vehicle, an air or vacuum chamber operating on the brake pedal of the towed vehicle with signal and air or vacuum supply from the towing vehicle. Motor home suppliers commonly use this system when setting up for a-frame towing.

RACQ Technical Services say the towed vehicle is regarded as a trailer and must comply with the mass limits and brake requirements for a trailer of that class, hence the need for brakes on the towed vehicle.

My experiences dealing with Qld. Transport and NSW RTA are that their regulations are ambiguous, open to interpretation, and no two officers will give the same answer to any enquiry.