Motorhome swaying at higher speed

[GBM]

Hello,
I purchased a 2003 Burstner Elegance A-class in May this year, it's a lovely vehicle with low miles and great condition. I noticed in my long drive home there was a tendency to start swaying at about 60mph. It was a bit unnerving, I slowed down rapidly and it recovered, but I'm wondering what the cause may be. Any clues?
Could it be tyres (Pressures? They were set at 4.5 bar all round at dealership), power steering? The van was unloaded but then it's 3.2t anyway. It's a Fiat Ducato 2.8 on an Alco chassis, no air suspension. The rear tyres are new, Michelin Triangle TR652 which I think could be a bit cheap, and Michelin Agilis Camping on front, fairly new. I could almost prevent it swaying if I was very delicate with the steering, is it just a question of acclimatising? I never experienced anything like this on my previous new coachbuilt Hymer. Any thoughts welcome.

 

[TheBig1]

It is the suspension getting tired. Best choice is to add airbags to the back axle first and if it lessens but still there, you need to start replacing the shocks and if needs be get the torsion bars in the axle refurbished by Fraser Brown Engineering. Each step gets more expensive

 

[pappajohn]

Are you sure of the weight.....
A 2.8ltr diesel and 3.2t

Anyway, in my opinion the tyre pressures are far too high.
That's the absolute max pressure for the tyre, not the actual running pressure.
Try 65psi rear and 56psi front.

Another cause of swaying is "tram lining"...... Stuck in the shallow depressions in the tarmac caused by thousands of truck tyres.
They will have a wider track so you are skipping from one to the other repeatedly.

 

[Guigsy]

The shock absorbers have probably leaked all their oil out and aren't doing any damping.

If your suspension is tired, then you will find that you'll turn and the body will lean and settle a short time after. So you have to be gentle on roundabouts and bends. I guess speed wobbles would be similar. Semi air suspension can help, but I'm not sure how easy is to fit to an old Alko.

 

[GBM]

Are you sure of the weight.....
A 2.8ltr diesel and 3.2t

Anyway, in my opinion the tyre pressures are far too high.
That's the absolute max pressure for the tyre, not the actual running pressure.
Try 65psi rear and 56psi front.

Another cause of swaying is "tram lining"...... Stuck in the shallow depressions in the tarmac caused by thousands of truck tyres.
They will have a wider track so you are skipping from one to the other repeatedly.

Ok,
Thanks for the reply. As mentioned the unladen weight is 3190kg, gross is 4000kg. The tyre pressures were at 65psi (4.5 bar) when the swaying happened. When I got home I checked the manual which states 5.5bar (80psi) for this chassis, so I upped them, but I've only done more local driving since, so I can't say what effect that has had. Knowing the weight per axle would be useful I guess before altering them front/rear?
I did wonder about the tramlining, but I never experienced that in my previous van which did a lot of motorway miles, that was one reason I was so surprised.

^{_{Subscribers  do not see these advertisements}}

 

[Nirvanauk]

At 80psi you'll lose all your fillings.

 

[GBM]

It is the suspension getting tired. Best choice is to add airbags to the back axle first and if it lessens but still there, you need to start replacing the shocks and if needs be get the torsion bars in the axle refurbished by Fraser Brown Engineering. Each step gets more expensive

Hi,
I'm going to experiment a bit with tyre pressures but if it's still a problem I'll take it in to see if any parts are due for change. Worn shocks should have been picked up during the MOT, done in May, though i can see why they might affect the van in a negative way, so worth a look.

 

[GBM]

At 80psi you'll lose all your fillings.

It's what the manual says.....!

 

[GBM]

The shock absorbers have probably leaked all their oil out and aren't doing any damping.

If your suspension is tired, then you will find that you'll turn and the body will lean and settle a short time after. So you have to be gentle on roundabouts and bends. I guess speed wobbles would be similar. Semi air suspension can help, but I'm not sure how easy is to fit to an old Alko.

Hi,
Yes, it's possible the shocks are past their best, I'm going to try altering pressures but if that's a dead end I'll take it in to see what they make of the condition of the shocks etc. It was MOT'd in May so faulty shocks should've been picked up. Not going to fit air, not worth the cost given the use its likely to get.

 

[Landy Andy]

I know you say you won’t fit air, but for £250 to £500 I wouldn’t want a van without it. Transformed the drive of my van, which is a similar age to yours. I adjust mine all the time, and feel the benefits.

^{_{Subscribers  do not see these advertisements}}

 

[DDJC]

I know you say you won’t fit air, but for £250 to £500 I wouldn’t want a van without it. Transformed the drive of my van, which is a similar age to yours. I adjust mine all the time, and feel the benefits.

Completely agree. We run close to max weight and going round the corner, the back wobbled like a three ton trifle on a trampoline.

Got VB semi air, with separate L and R, compressor and gauges, and it is solid on the road, corners and straights. I stick about 2.5 bar in and I don't get airbumped by overtaking lorries or if I am overtaking them. Going over the crappier concrete parts of the southern parts of the M25, doesn't cause the bump stops to sound like a day at Larkhill artillery ranges.

And, on site, careful use of them means that the ramps stay in the garage.

And it gives me two more switches to fiddle with

Like Andy, I will never have another van without semi air or air.

 

[BouncyBoatFolk]

I know you say you won’t fit air, but for £250 to £500 I wouldn’t want a van without it. Transformed the drive of my van, which is a similar age to yours. I adjust mine all the time, and feel the benefits.

+1.
Mike.

 

[1967bowesj]

I know you say you won’t fit air, but for £250 to £500 I wouldn’t want a van without it. Transformed the drive of my van, which is a similar age to yours. I adjust mine all the time, and feel the benefits.

Op says van is on an Alko chassis so won’t be that cheap to fit air, could be the tube axle is worn?

 

[donkey]

Before you fork out for any new/extra bits, you need to get the van weighed in ready to travel trim You need rear axle weight, front axle weight and total weight. Only then will you be able to rule out poorly distributed loads and/or overloading.

Geoff

 

[Brains]

I know you say you won’t fit air, but for £250 to £500 I wouldn’t want a van without it. Transformed the drive of my van, which is a similar age to yours. I adjust mine all the time, and feel the benefits.

Out of interest.
Ex landy owner (learned to drive in a SII, owned Landies for over 20+ years)

Now driving a 4t Merc Sprinter based 6.7m Hymer that is 3m high and wobbles like a beanpole on a trampoline.
What could I install that would settle things down a bit

^{_{Subscribers  do not see these advertisements}}

 

[Barclaybasher]

Another vote for air on the rear (£300 -500) stabilises the van.

Tyre pressures - I run at 86psi as recommended by someone who's been fitting tyres all his life.

 

[Mikeyv60]

At 80psi you'll lose all your fillings.

That what Fiat sets their tpms to

 

[pappajohn]

Ok,
Thanks for the reply. As mentioned the unladen weight is 3190kg, gross is 4000kg. The tyre pressures were at 65psi (4.5 bar) when the swaying happened. When I got home I checked the manual which states 5.5bar (80psi) for this chassis, so I upped them, but I've only done more local driving since, so I can't say what effect that has had. Knowing the weight per axle would be useful I guess before altering them front/rear?
I did wonder about the tramlining, but I never experienced that in my previous van which did a lot of motorway miles, that was one reason I was so surprised.

My mistake, I was thinking 4.5 bar was 80 psi.
5.5bar is far too high, that's the max pressure for that tyre plus michilin camping tyres are extremely hard and will give a harsh ride at any pressure.
Problem using axle weights to calculate pressures is you need to be in holiday trim to get weighed as you have all most a ton difference between unladen and fully laden which will obviously alter the required pressure.
Load up and visit a weighbridge then email michilin with the axle weights

 

[Nirvanauk]

That what Fiat sets their tpms to

Yikes!

 

[Live Life Now]

Some very savvy and knowledgeable funsters on here and I have learnt a lot from them, however, did you buy from a dealer? and if so before experimenting I would check to see what warranty you have.
It's well known that many an experimenter has breached the warranty condition because of some very minor adjustment, just a thought.
Good luck and I hope you sort it out soon.
Happy MHoming from another at Dorset

^{_{Subscribers  do not see these advertisements}}

 

[TheBig1]

Always remember that very few garages know how to grease or test torsion bar suspension axles. That is why there is one main supplier that refurbishes them in the UK. Definitely an interesting process

 

[Otter Spotter]

That what Fiat sets their tpms to

And the first thing you do is get the tpms reset at fiat dealers

 

[Cookieboy68]

Are your tyres old,if they are could be the side walls have lost their integrity.
The dealer we got our 2002 hymer from said when he drove it home after buying it said it was a very hairy drive.It was down to the van being sat for a couple of years and the tyre side walls had given up. Just a thought

 

[Barclaybasher]

The reason to run tyres at higher pressures is because your motorhome is running as if it was a fully laden 3.5t van - all the time

 

[Emmit]

It's what the manual says.....!

It say INDIA on my tyres but they've never been there.
Sorry, I'll get me second coat.

^{_{Subscribers  do not see these advertisements}}

 

[royandsharont]

I found that my 4t 3m high coach built used to sway like you describe at around 65mph from new and always did. I took it to be the height and wind effect

 

[Lenny HB]

I know you say you won’t fit air, but for £250 to £500 I wouldn’t want a van without it. Transformed the drive of my van, which is a similar age to yours. I adjust mine all the time, and feel the benefits.

It's an Al-Ko chassis so more like £2½k.

 

[pappajohn]

Are your tyres old,if they are could be the side walls have lost their integrity.
The dealer we got our 2002 hymer from said when he drove it home after buying it said it was a very hairy drive.It was down to the van being sat for a couple of years and the tyre side walls had given up. Just a thought

OP says rear are new and fronts almost new.

 

[Cookieboy68]

OP says rear are new and fronts almost new.

Doh,I'll read things properly in future

 

[BouncyBoatFolk]

Another vote for air on the rear (£300 -500) stabilises the van.

Tyre pressures - I run at 86psi as recommended by someone who's been fitting tyres all his life.

86psi, not heard or seen that recommended anywhere, I think my bus would be like Coco the clowns car going down the road, arriving missing many panels and structural components.
Mike.