Citroen XM Forum

So, exactly what were the Comfort spheres like to drive, apart from not good?
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2.5 pressures are 2.3 bar FF, 1.9 bar RR. That's from the original 1996 owner's manual. Haynes Book of ***** says 2.3 for both FF and RR, which is just plain wrong, and leads to a hopelessly thuddy, crashy and skippy back end.

It is funny, the tyre pressures must be exactly right for the ride to be good. When I got mine, the pressures were far too high, and the ride was bad for it. Much better now the tyres are at the right pressures.

2.3bar front and rear is correct for an XM estate.

John

White Exec wrote:So, exactly what were the Comfort spheres like to drive, apart from not good?
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2.5 pressures are 2.3 bar FF, 1.9 bar RR. That's from the original 1996 owner's manual. Haynes Book of ***** says 2.3 for both FF and RR, which is just plain wrong, and leads to a hopelessly thuddy, crashy and skippy back end.

It's OK on good roads (driving in France on the autoroute it's good) but on bad roads it's like driving a car with worn shocks and cornering isn't as it should be.

It's OK on good roads (driving in France on the autoroute it's good) but on bad roads it's like driving a car with worn shocks and cornering isn't as it should be.
Hmm. Presumably 'Comfort' spheres owe their origins to pre-Hydractive days, when there were no centre spheres. With a 6-sphere setup, coupling Comforts with additional centre units probably overdoes the resiliance, and together with the reduced damping (larger orifices) takes away the stability and precision that the XM was designed to have.
Our 'problem' is with low-speed bumps, and not with high-speed Normal (= Comfort) running, so we're back to looking at damping orifices?

It is funny, the tyre pressures must be exactly right for the ride to be good. When I got mine, the pressures were far too high, and the ride was bad for it. Much better now the tyres are at the right pressures.
Russ, this absolutely corresponds to my own experience. Over-inflation immediately wrecks the ride on a poor road surface.

I drove drilled out spheres in the Xantia and they were perfect. I hated the ones on the XM but I don't know where they came from. I think you are right with the 6 sphere set up.

White Exec wrote:It's OK on good roads (driving in France on the autoroute it's good) but on bad roads it's like driving a car with worn shocks and cornering isn't as it should be.
Hmm. Presumably 'Comfort' spheres owe their origins to pre-Hydractive days, when there were no centre spheres. With a 6-sphere setup, coupling Comforts with additional centre units probably overdoes the resiliance, and together with the reduced damping (larger orifices) takes away the stability and precision that the XM was designed to have.
Our 'problem' is with low-speed bumps, and not with high-speed Normal (= Comfort) running, so we're back to looking at damping orifices?

I could well be wrong, but I was always under the impression that comfort spheres were primarily intended as a 'quick fix' to make cars which were stuck in hard mode tolerable...

Comfort spheres are really for non-hydractive cars and to fit them as corner spheres is wrong.

The way to achieve a really complaint ride on an XM would be to alter the centre dampers, so that the car is softer in soft mode, but still safe and taught when cornering or otherwise in hard mode.

I have drilled my front spheres to 0.7mm, which is the same as the 2.0i or series 2, V6 and TD. I suspect these spheres are not original and ride harder as a result, whereas the IFHS ones ride very nicely as made.