Thread: DSC on or off when towing a van

this is new, il be watching the out come of this, plz tell me you dont have load levelers on do you, they fite with the air sus and play big time with the handling

DSC definitely on. If the car is being moved about by the trailer to the extent that DSC activates then you need to reorganise your tow setup asap as the trailer is exerting forces it should not be on your vehicle.

If the trailer lacks directional stability that is usually indicative of too low a towball mass, or possibly a correct towball mass with significant weights a long way from the CoG. I would also be checking tyre pressures all round and increase for towing on the towcar.

You must get this fixed asap because the conditions you describe mean the rig will be very prone to trailer sway and that could be deadly. I would fix the base setup issue rather than mask it with kit like anti-sway bars.

Also need to make a general allowance for the 2000kg 20" which is not a trivial tow, it will feel different to the lower, lighter poptop.

Best of luck and let us know how you get on.

Hi Pete,
I agree with Robert. You need to have a look at your tow setup.
My boat is around two tonnne and have noticed that when we go away with the boat fully loaded with our gear, the vehicle handles better with most of the gear towards the rear of the boat, not the bow.
Normally, you would think that more weight on the ball would work better, but that isn't the case with my setup.
Cheers, Craig

D4SE, don't doubt your point but I'm concerned someone may read your post and then load towards the rear which is more dangerous than loading the front.

Trailer setup with the larger rigs can be tricky and it is definitely (literally and metaphorically) a balance. A lower towball mass (TBM) will improve responsiveness and make the rig easier to turn, it'll feel nimble. However, you lose directional stability and start to run the risk of trailer sway at speed. Not nice at all.

Loading up the TBM makes the thing feel heavier and less nimble, but is more stable and less chance of sway. However, it can be too stable and difficult to change direction. Also, once the trailer is knocked out of balance it requires more force to bring it back into line.

One mistake is to get the TBM right but by using heavy weights at either end. This gives an effect similar to high TBM - difficult to overcome the interia to turn the trailer, but if it is overcome it doesn't want to stop. Weights should ideally be as close to the CoG as possible.

The correct TBM should be supplied by the trailer manufacturer and should be less than the lower of the vehicle's TBM and the towbar's TBM. The latter two are not necessarily identical. Also if your towcar is at or close to GVM then the TBM will be reduced so as not to exceed the rear axle load limit.

Common misconceptions:

- my car can tow 3500kg, therefore anything like 2000-2500 is no drama at all just hook up and go
- it all feels fine so far, so good (wait till you hit a big gust at 110 or hit an off-camber windy patch on wet bitumen)
- if the car has the grunt to move it, all good (excess power and torque is about the least important criteria for a safe towcar)
- don't notice the trailer on the back so all good (wait till you need to brake hard or similar...then anything other than a good setup will bite, and bite hard)

that's enough, train about to arrive ;-)

Hi Robert,
Totally agree with the theory not to load the rear of the boat / caravan etc. Been towing all my life and know this for a fact.
I am forever telling my guys not to load the back of the rubbish trailer too much as it causes sway.
However, for some reason it worked with my boat scenario???
Cheers, Craig

Thanks all for your comments. Firstly, my D3 is an'S' with all coil suspension. Rear wheels are up to 42 psi as per LR tyre guide. The caravan is dual axle with the wheels set well back making for a long "A" frame. The bed is at the front with very little weight in the underneath storage. About all that is behind the wheels is the fridge and the ensuite. But their is much greater weight on the rear of the car with this van, since the rear still sits down a bit despite the Hayman Reese WDH which I believe is able to be used on an all coil suspension D3. I am loath to add anymore weight to the front of the van because the car will just sit down further. I am considering fitting Polyair adjustable air bag inserts on the rear of the car to bring the rear up to level.

Thanks again, Peter

Hi GP,
Our setups are different, but I can only give you my experience.

Like you, I have a coiler, but the coils are King Springs, giving a 50-60mm lift (& 30% stiffer than original). As I didn't tow the caravan with the D3 before the spring change, I don't know what effect this mod has had.

My 'van is a 1500(?)kg single axle pop-top, so again, different to you.

I have a Hayman Reece adjustable hitch. With this, I have set the 'van to be perfectly horizontal when everything is loaded.

I keep the 'van tyre pressures high.

My Hayman Reece hitch has provision for WDHs (that I used to use on my D1), however, I have never felt the need for them with my D3.

So some questions:
1. Is your 'van chassis horizontal when connected to the D3? If not, this may placing more load on one of the axles.
2. What is the 'van towball mass as against manufacturer's recommendation?
3. What are the 'van tyre pressures set to as against manufacturer's recommendation?
4. Are you considering going off-road with your D3? If yes, then may I suggest the King Spring lift (or similar) as the D3 LR coils are set to about the same height as the air sprung on-road setting. If not, the Polyair's may help.

I'm sure that there are some things that I've forgotten, but your responses to the above would be a useful start.

HTH,
Peter
PS: If you lived nearby, you could try my D3 with your 'van.

Hi Pete,
The Polyair bags are a good idea. Had them on several vehicles.
Mind you, the ride is as rough as hessian undies once you unhook the van.

Craig