Ducato suspension. (1 Viewer)

[Vadre Smith]

I have had 4 trips out in my 2011 Autotrail Excell 590 EK and am wondering if the harsh suspension is normal or do I have a problem.
On smooth roads it is fine but any poor surfaces or potholes finds it really slamming in at the rear.
I have fitted air suspension in place of the standard bump stops. This does feel a little better but its far from perfect.
This is a sub 6 metre coach built so maybe the short wheelbase is a factor.
Any thoughts?
Thanks.

 

[StitchesnFluff]

Tyre pressures too hard

 

[icantremember]

Tyre pressures too hard

Or air bags over-inflated?

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[Vadre Smith]

Thanks for your replies.
Tyres are 72 psi front and 80 psi rear.
Air bags 2 bar (30 psi)

 

[Techno]

Tyre pressures too hard

Or air bags over-inflated?

Both

 

[Techno]

Michelin always quote 80 psi rear regardless of weight and it is simply too much

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[pappajohn]

My last motorhome tyre pressures were 80psi all round with rear airbags at 65psi
It was 7500kg and 33ft long including a 10 ft rear overhang..
My last european van was 24ft and 3850kg.
Fronts 58psi
Rears. 62psi

Maybe says something about your tyre and airbag pressures.

 

[Ed Excel]

The Excel has a very harsh ride. It has twin leaf springs on the back, so the suspension is quite stiff. One thing you should never get is a sagging back end. I replaced the bump stops on mine with softer rubber spring assistors; still didn't make much difference to the crashing over rough surfaces. I can't see how air bags would help, surely that's stiffening the suspension even more. If you have Motorhome type tyres fitted, changing them for standard tyres should help, by taking the stiffness out of the sidewalls. Finally, as suggested, match your tyre pressures to your axle weights. Hope that helps; I'm on a second set of dentures lol.

 

[WillH]

Lower your tyre pressures a bit at a time until you get a balance between comfort and handling, then check that they are not wearing unevenly. Took me about three months to get mine sorted.

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[mikebeaches]

I've always thought the Ducato rear suspension is a bit agricultural, to say the least. But your tyre pressures are way too high, which will make it much worse.

No knowledge of the air suspension, so can't comment on that.

 

[Hymie]

Mine's an older Hymer, TP is marked on wheel arches at 62psi front & 64psi rear, air suspension is set at 2 bar, still feels like someone hit it with a sledge hammer on any potholes.

 

[Vadre Smith]

Ok so I am not expecting it to ride like a Lexus but it seems I need to experiment/research tyre pressures to see if this softens it a bit.
Thanks to all so far.

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[Gorse Hill]

I have AS and always thought 3 or 4 bar standard as indicated by manufacture TP 65psi
Van 3500 and 7 meters

 

[Ranger]

When you stop for a break after a run immediately place your hand on the tread of each tyre. If it is hot its underinflated or overloaded, if cold its over inflated and if just warm it will be about right and not stressed. Do also remember that it is a legal requirement in the UK to have the correct tyre pressures but what is the correct pressure?

 

[Techno]

Best thing is weigh both axles and then email Michelin for pressures BUT instead of asking for front and rear ask for front at pressure A
And FRONT at pressure B (rear)
They will say 80 psi for rear regardless

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[Figaro]

I think Michelin have a standard reply to all motorhome tyre pressure enquiries whatever weights you give them.
I've seen replies posted on here identical to the reply I received and 80 psi does seem to give a harsh ride so I think I'll drop mine to 70 and see what that's like

 

[Speve]

I have Michelin Agilis campers on our Hymer run at 5 bar rear and 4.5 bar front when loaded seems to do the trick

 

[denisejoe]

What is the max pressure on your tyres mine are only 70psi

Joe

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[Lenny HB]

What is the max pressure on your tyres mine are only 70psi

Joe

If you are referring to the markings on the tyres that is only for the USA.

 

[denisejoe]

What's the max pressure for toyo ho9 then never felt the need to go that high anyway

Joe

 

[denisejoe]

If you are referring to the markings on the tyres that is only for the USA.

Not according to

Joe

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[Emmit]

What's the max pressure for toyo ho9 then never felt the need to go that high anyway

Joe

I've had a look and it would appear that the Toyo tyre is a winter Van tyre.
From all I've read, seen etc, a 'van' tyre, as opposed to a camper tyre, shouldn't be taken above 65psi.
I use a van tyre on our 3700kgs Hobby and at 1700kgs front and 2000kgs rear I'm running at 54psi front and 62kgs rear

 

[TerryL]

The standard Fiat Camper chassis can never be very smooth, as it is just a pair of cart springs. Replacing the rubber bump stops (which are actually spring assisters) with air units won't improve the crashing ride but will improve the handling. I know, I've done it.

But as almost everyone has said, the problem is your pressures are way too high and the only way you're going to be bombproof with the law is to get proper recommendations from the tyre manufacturer. If they won't play ball, and I'm surprised about Michelin, you're a bit stuffed. The Tyresafe website ( http://www.tyresafe.org/) has some useful info.

I use Continental Vanco 2 Winter tyres all year round and have found their technical dept quite helpful. 56 psi front and 65 psi rear.

 

[Vadre Smith]

Thanks to all for your help with this.
We are off to Slinfold on Friday. I have dropped the tyre pressures to 58 (F) and 62 (R). See how it goes while keeping a close eye on handling and tyre temperatures.

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[denisejoe]

Toyo h08 has 70psi on tyre

 

[Louis]

Thanks for your replies.
Tyres are 72 psi front and 80 psi rear.
Air bags 2 bar (30 psi)

Front should be higher than rear, Try 65 lbs all round till you get the correct pressure confirmed

 

[Puddleduck]

We have Continental tyres on our van, we got it weighed fully loaded and both axle weights then asked Continental for their recommendations. Since making sure we stick to the Conti pressures the ride is so much better!

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[Vadre Smith]

Ok so our trip to Slinfold, about 35 miles with reduced tyre pressures showed some improvement in the ride. Still no Lexus, but only the worst road defects were causing crashing at the rear.
Tyres on arrival were warm to the touch but certainly not hot.

Thanks to all for your input, next step is to find out exactly what tyre pressures I should be using by contacting Continental.