Ballast when towing?

I was under the impression that UK drivers had the option of electric trailer brakes -- which are not allowed here in the EU -- but I realize now I was thinking of some Aussie forums I have been on.

By the way, I have used the electric brakes extensively when traveling in the USA, and I assume the reason they are not allowed here in the EU is because they are too cheap and effective. French and Germans prefer things that are complex and expensive, so they can write more regulations about them, so we don't get fun toys here.  Like 4-door Jimnys for example...

But UK people don't have such bureaucratic overhead, so it should be easier to have such things.  (So why not a campaign to force Parliament to allow the Maruti extended Jimny?  You could block the roads with Jimnys like the French farmers do with their tractors.)

Just another thought... I've only ever had non-abs Jimnys, which have the load sensing valve on the rear brake circuit. As such, the extra nose weight of the trailer will shift the valve to increase the braking force on the loaded rear axle. ABS equipped Jimnys do not have this valve, so the brake bias will not change to account for the trailer. This strikes me as an inferior setup, as the the only way you'll benefit from the extra grip of the rear tyres is when the front tyres start skidding.

I'm also unsure why you think ballast should be added to the rear of the car. Isn't the trailer already doing that? And as the trailer brakes come on, it will increase the weight transfer onto the car.

The thought was that if the car as a unit was heavier it both increases it's traction and also allows the overrun to push harder against a greater inertia. Think double headed trucks moving a piece of mining equipment where the front truck has a weight block over the rear axles instead of a 5th wheel. It provides the front truck with inertia for stopping and traction for pulling. Scaled-down obviously and not double-headed though a tandem jimny tow rig would be something to see.

Busta wrote:

Just another thought... I've only ever had non-abs Jimnys, which have the load sensing valve on the rear brake circuit. As such, the extra nose weight of the trailer will shift the valve to increase the braking force on the loaded rear axle. ABS equipped Jimnys do not have this valve, so the brake bias will not change to account for the trailer. This strikes me as an inferior setup, as the the only way you'll benefit from the extra grip of the rear tyres is when the front tyres start skidding.

I'm also unsure why you think ballast should be added to the rear of the car. Isn't the trailer already doing that? And as the trailer brakes come on, it will increase the weight transfer onto the car.

Jimnys with ABS don't need the load sensing valve. ABS works by sensing each wheel and applying the principle of cadence braking. As such it is much more accurate than a simple load sensing valve.. The brake bias will change to suit the situation and not to just front/rear  but to each wheel as required. As a wheel starts to lock up, the ABS kicks in and the braking effort is modulated so lock up is controlled. 
Many problems associated with towing, whether it is a trailer or a caravan are due to lack of brake maintenance. When a car brakes, the overrun operates and applies the brakes on the trailer. If the brakes on the trailer operate correctly, they should be responsible for all the necessary braking on the trailer, the cars brakes slow the car and the trailers brakes slow the trailer. I built an "A" frame to tow my SJ behind the LC. The SJ's brakes were operated by a bowden cable that was operated by movement of the "A" frame sliding joint. The system was very smooth and car braking was no different indicating that the SJ,s brakes were working as they should.

Roger

Lambert wrote:

The thought was that if the car as a unit was heavier it both increases it's traction and also allows the overrun to push harder against a greater inertia. Think double headed trucks moving a piece of mining equipment where the front truck has a weight block over the rear axles instead of a 5th wheel. It provides the front truck with inertia for stopping and traction for pulling. Scaled-down obviously and not double-headed though a tandem jimny tow rig would be something to see.

I understand the principle of using ballast to make the tow car heavier. I'm just not sure why you'd want to add that ballast to the rear of the car, other than because it's the easiest place to put it.
A truck is designed to carry around 1/3rd of the trailer weight through the 5th wheel, so for a standard artic that is in the region of 10t. When pulling on a bar it is not getting any weight transfer from the load, so it needs weight over the driven wheels just to function. Your Jimny is designed to work perfectly well with no load or trailer on the back. Adding a trailer increases the load on the rear axle and slightly reduces the load on the front axle. Even with a trailer on, it's still the front wheels that do most of the stopping so in my mind it would make sense to add the ballast as far forward as possible.

You mean like a nose box on the front 3 point? I get what you're saying about it all being in the back and that being where the imposed load of the trailer is but being a twin the nose weight is more uniform than if it were a single, I have never really felt it pitches that much. The other easier way is a passenger but I don't always have one available.