Problems when towing!

[AnnM1]

Is anyone else the owner of an Award Dawnstar? Do you have problems when towing?

When overtaking lorries on the motorway (no more than 60 mph) we experience the van being pulled towards the lorry(s). Very frightening and the only way to stop this happening is to slow down and let the van settle. We are very careful when loading and ensure that the nose weight is correct.

As this has never happened to us before - could it be something to do with the layout of the van itself? It has an end bathroom and 'L' shaped kitchen. We are thinking of changing the van at the beginning of next year but would to hear if anyone has the same problem.

It would appear that this year (2006) this particular layout has been dropped by the Swift Leisure Group. Suspiscious or what?

 

[Lutz]

The interior layout of the caravan has no bearing on its handling. Apart from the obvious criteria which one is able to influence by one's self such as proper loading, setting the correct noseweight and tyre pressures, designwise a long drawbar helps. Some caravan manufactuers try to maximise interior space by providing a long body while keeping overall length to a minimum with the result that the drawbar becomes very short. This is anything but ideal. Maybe a different make of tyre with stiffer sidewalls would also help.

 

[ProfJohnL]

Hello Ann

I Agree with Lutz on this one, but would add that the effect you describe is almost certainly related to the aerodynamics of the combinatoin of the car and caravan. Change one or the other and the effect will be different.

The wind strength and direction could also have been a significant factor, and your difficulty may not arrise on a different day or on a different heading realitve to the wind.

 

[RogerL]

Ann - dropping the Dawnstar may not be suspicious at all.

Far fewer couples are buying 2-berths as 4-berth or fixed bed layouts are more popular. Swift may simply be reflecting customer demand by dropping smaller models and introducing larger ones.

Has this been a problem all the time you've had the Dawnstar. You don't say what you're towing with, or give any weigts so it's difficult to add to the general comments given by Lutz and John.

 

[mike_5041102]

Make sure you are towing close to 85% and in any case less than 100%. Best thing by far is to try towing with a different car, preferably one that is heavier. I did this and quickly learnt that the rear suspension on my car was just not robust enough for a 1300 kg caravan.

 

[Lutz]

I get the impression from Ann's question that she had been towing with a caravan of similar weight before and only had the problem since changing to one with an end bathroom. If this is the case, the cause can't be an unfavourable weight ratio. A heavy towcar is not the only criterion which ensures a stable outfit.

I'm a bit puzzled by your statement that the rear suspension of your car was 'not robust enough' for a 1300kg caravan. What do you mean by that?

 

[mike_5041102]

Perhaps 'too soft' would be a better description, and the overhang was very long which didn't help either. I agree weight is not the only criterion, just one of the more important ones. Would be interesting to know if Ann has changed the rear tyres since towing the older 'van

 

[Lutz]

A soft rear suspension and/or tyres with soft sidewalls probably contribute as much to instability as an unfavourable weight ratio.

Another important factor which Ann didn't mention is what the weather conditions were like when the new caravan was being towed. If it was a windy day, it is only to be expected that the outfit will seem twitchy.

 

[Steve L]

As suggested before it might be a design fault for instance if the rear length from the axle back wards is greater than the distance from the axle to the front of the van. This could cause instability.

I must admit that a lot of lorry drivers do like to play games, by driving close to cause a van to sway.

What I do is to keep an eye on the traffic behind. When a lorry or coach is approaching to overtake, I move to the far right of my own lane. This usually edges them out to do the same. Then just as they are about five yards away I move to the far left of my lane, thus gaining the max space between us which usually gives a wobble free trip.

Obviously when doing this you MUST be sure not to cause any distress or danger to other road users.

Try it and see if that helps the drive.

Steve.

 

[Lutz]

I don't know of any caravan on the market, even a poorly designed one, where that's the case, Steve (that the body of the 'van behind the rear axle is longer than the rest ahead of the axle). Perhaps you might let us know which model you are referring to.

Actually, so long as the correct noseweight is maintained, it doesn't really matter where the centre of the 'van's body is relative to the axle. Both ahead and behind the axle are just as bad. Ideally, the centre of the superstructure should be right over the axle. Otherwise, any crosswind is going to have the effect of trying to rotate the caravan about its vertcal axis.

 

[RogerL]

Some HGVs create a much bigger bow-wave than others despite all being roughly the same size and shape. This bow-wave can also be noticed with on-coming HGVs on single carriageway roads. Most cause no disturbance, a few cause buffeting to the wing-mounted mirror and the odd one causes enough disturbance to fold the mirror back.

There is some university research going on into this as a reduction in bow-wave will improve HGVs fuel consumption as well as generating less disturbance for other vehicles.

Crosswinds normally affect larger caravans much more than smaller ones, as their sail area / side profile is much larger. The Dawnstar is a smaller Award.

I'd still like to hear from Ann identifying the towcar and giving it's kerbweight and the caravan's MTPLM and noseweight.

 

[AnnM1]

Ann - dropping the Dawnstar may not be suspicious at all.

Far fewer couples are buying 2-berths as 4-berth or fixed bed layouts are more popular. Swift may simply be reflecting customer demand by dropping smaller models and introducing larger ones.

Has this been a problem all the time you've had the Dawnstar. You don't say what you're towing with, or give any weigts so it's difficult to add to the general comments given by Lutz and John.

Hi Lutz and John

We have only experienced this problem since changing both our units. We have towed for 20+ years and never experienced this phenomena.

Our new unit consists of Volvo Cross Country estate/Ace Award Dawnstar. The Volvo is the 'highly' tweeked turbo, but I don't think this should cause any problems. We check the tyres prior to taking to the road on both units and, as we have a motor move, it is important that we do this since we have a very steep, bending driveway to negotiate.

We check the nose weight of the van with a nose gauge (probably not that accurate but next to the best thing).

Both vehicle and van are very heavy, but having read all the documentation and talked to the dealers, had confirmation that we should have no trouble.

Towing normally causes no problems. Only when overtaking slow lorries, when we have to negotiate the middle lane.

We have taken the van in for its first service and have arranged for the 'pads' on the Alko to be replaced. We will also ensure that the towball is well and truly cleaned before going off again. Hopefully, this will help.

The other half is talking about getting rid of the van, although we both like it, as we feel very vulnerable on the road.

 

[AnnM1]

As suggested before it might be a design fault for instance if the rear length from the axle back wards is greater than the distance from the axle to the front of the van. This could cause instability.

I must admit that a lot of lorry drivers do like to play games, by driving close to cause a van to sway.

What I do is to keep an eye on the traffic behind. When a lorry or coach is approaching to overtake, I move to the far right of my own lane. This usually edges them out to do the same. Then just as they are about five yards away I move to the far left of my lane, thus gaining the max space between us which usually gives a wobble free trip.

Obviously when doing this you MUST be sure not to cause any distress or danger to other road users.

Try it and see if that helps the drive.

Steve.

We only experience this problem when we are actually overtaking! Have no problems with lorries overtaking as my husband is very aware of this situation>

 

[AnnM1]

Hi RogerL

I have responded in the 'Comment' section to Lutz, John and Steve in Leo. Hopefully, this has helped with the question.

Ann

 

[Steve L]

I don't know of any caravan on the market, even a poorly designed one, where that's the case, Steve (that the body of the 'van behind the rear axle is longer than the rest ahead of the axle). Perhaps you might let us know which model you are referring to.

Actually, so long as the correct noseweight is maintained, it doesn't really matter where the centre of the 'van's body is relative to the axle. Both ahead and behind the axle are just as bad. Ideally, the centre of the superstructure should be right over the axle. Otherwise, any crosswind is going to have the effect of trying to rotate the caravan about its vertcal axis.

I have seen one van like this I think it might of been a dutch outfit.

Actually a longer distance between axle to the front doesn't have quite as strong affect as there is the weight and motion of the tow car to counteract. A longer rear overhang does have some weight of the car to counteract, but mostly the only stabilising "dead" weight comes from the van it's self.

I've towed those very unwieldly looking glider trailers and boy oh boy in a cross wind they are a right pain. My mate moved the axle back on his by a whopping 4 feet which only added 30Kgs to the nose weight of the loaded trailer and still only making 80Kgs of nose weight to the car. This dramatically improved stability but tight junctions are a bit of a struggle as you need all the road going out to get round.

Steve.