Technical Suspesion
- Thread starter hymer
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Technical Suspesion
If you're talking about that back and it is a ducato chassis and its sitting on the suspension cones then air or an assister leaf might help. But if its an alko chassis with a ducato cab then if may be torsion bars are broken or need greasing.
Check your rear tyre pressures....if 70 to 80 PSI (as recommended by FIAT for the base vehicle) contact the tyre manufacturer with the maximum load weight for the correct pressure.....Google for the vast number of answers on the subject.
Even then Michelin, for example, are now recommending 80 PSI whereas most users run at between 50 to 70 as recommended by them previously.
Even then Michelin, for example, are now recommending 80 PSI whereas most users run at between 50 to 70 as recommended by them previously.
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...Michelin always used to quote rear-axle pressures for motorhomes on "Camping" tyres closely in line with those in the Tyresafe booklet. (Historically, I've had several eMails from them recommending much lower than 80psi).
They then switched to recommending only 80psi, whatever the actual axle loading. Continental are still somewhat less conservative.
For most 'vans, this pressure is filling-threateningly jarring, and reducing pressures has for me resulted in much-improved ride and handling.
My last two motorhomes have both been disposed of at 5 years (and around 30k miles) with still years of tread left.
If I were you (if only as an experiment) I would check your fully-loaded axle weights on a weighbridge, and try front and rear pressures as specified in:
http://tyresafe.org/images/tyre-safety-guide/motorhome-leaflet.pdf
...allow a margin if you wish (I do) and then decide if you really need to sort out your suspension.
I'd be surprised if you didn't notice quite a difference.
(as an example, this was a quote from them in the past for 215/75 R16CP (Camping) tyres where the default of 80psi was on the vehicle label.
The pressures that we would recommend based on the loads quoted are as
follows;
> -
>
> Front axle 1850kg - 60psi
> Rear axle 2120kg - 64psi.)
And that was based on the Maxi maximum axle weights - I was running below these, but used the quoted pressures.
I understand they used to "up" the front pressure quote slightly to allow for weight transfer under braking.
They then switched to recommending only 80psi, whatever the actual axle loading. Continental are still somewhat less conservative.
For most 'vans, this pressure is filling-threateningly jarring, and reducing pressures has for me resulted in much-improved ride and handling.
My last two motorhomes have both been disposed of at 5 years (and around 30k miles) with still years of tread left.
If I were you (if only as an experiment) I would check your fully-loaded axle weights on a weighbridge, and try front and rear pressures as specified in:
http://tyresafe.org/images/tyre-safety-guide/motorhome-leaflet.pdf
...allow a margin if you wish (I do) and then decide if you really need to sort out your suspension.
I'd be surprised if you didn't notice quite a difference.
(as an example, this was a quote from them in the past for 215/75 R16CP (Camping) tyres where the default of 80psi was on the vehicle label.
The pressures that we would recommend based on the loads quoted are as
follows;
> -
>
> Front axle 1850kg - 60psi
> Rear axle 2120kg - 64psi.)
And that was based on the Maxi maximum axle weights - I was running below these, but used the quoted pressures.
I understand they used to "up" the front pressure quote slightly to allow for weight transfer under braking.
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..edited to Add.
Your vehicle could just as easily have been fitted with Continental Vanco camper tyres, and the "recommended" Fiat pressures would still have been the same.
Continental will, however, recommend lower pressures where appropriate if the axle loadings allow.
Their data tables are also freely available. If you prefer, you may wish to find your equivalent sized "Camper" tyre (I'm assuming you have these if you're using 80psi) in their tables, and use pressures from there.
http://www.continental-tyres.co.uk/...ervices_uk/resource_library/bulletin_6_en.pdf
...pages 72 thru 79 depending on tyre size.
Your vehicle could just as easily have been fitted with Continental Vanco camper tyres, and the "recommended" Fiat pressures would still have been the same.
Continental will, however, recommend lower pressures where appropriate if the axle loadings allow.
Their data tables are also freely available. If you prefer, you may wish to find your equivalent sized "Camper" tyre (I'm assuming you have these if you're using 80psi) in their tables, and use pressures from there.
http://www.continental-tyres.co.uk/...ervices_uk/resource_library/bulletin_6_en.pdf
...pages 72 thru 79 depending on tyre size.
Hugh is perfectly correct.
I run my Autotrail Tracker at 50PSI front and 55 PSI rear as recommended by Michelin.
They are the latest Agilis Campers.....the third set on my current vehicle and 50K miles with completely acceptable wear......I change at 5 year intervals.
I run my Autotrail Tracker at 50PSI front and 55 PSI rear as recommended by Michelin.
They are the latest Agilis Campers.....the third set on my current vehicle and 50K miles with completely acceptable wear......I change at 5 year intervals.
+1 for hugh advice follow the tyre safe guidlines 80 psi is insanely high pressure (unless you have a 4500kg+ behemoth but then it should really be on larger rims and tyres) especially in the back where it doesn't get load transfer under breaking.
When I hear motorhome owners talking about tyre wear and fancy tyres I just look at the odometer. Most of them do 500-5000 miles a year. The tyres will have perished long before tyre wear is an issue.
When I hear motorhome owners talking about tyre wear and fancy tyres I just look at the odometer. Most of them do 500-5000 miles a year. The tyres will have perished long before tyre wear is an issue.
Last edited:
blaven
Member
If you decide you still fancy air suspension on the rear, its available from Marcle Leisure in Ledbury. I've just fitted a kit onto my 2003 X244 2.8JTD. Its a kit using Dunlop units. Pretty straightforward.
More like 20psi....I've been running 50F and 60R for 15000km now and NO uneven wear, no overheating, good ride and no handling problems. My unit weighs just over 4ton. 1.9F and 2.2R when fully loaded for a trip. I travel at 100kph where appropriate.
Most of us don't ever wear out these tyres. I replace mine every 5 years to guard against delamination etc. 5 years usually means about 40K and the tyres are not worn out at that mileage. Why put up with a bone-jarring ride??
Ian.