Citroen XM Forum

Hi guys,

What id like to know is the pressure ratings of original Xm spheres...i have seen comfort spheres listed on AEP which i presume are again different, With Xantias you can use all sorts, non hydractive on hydractives, petrols on diesels etc...I know i have a mix fitted on my Xantia which has tuned the ride to how i like it. Id like the XM to be as per factory spec...as from what you guys say they are nice and soft.

iirc, Your car is to be a 2.1Td, so, 62 Bar for the accumulator, 450cc-50bar-0.8mm damper for the fronts, 400cc-30Bar-0.7mm damper for the rears, 450cc-50Bar for the front centre and 400cc-50Bar for the rear centre.

Increasing pressure reduces the spring rate, making the damper larger alters the damping frequency.

They are the same as Hydractive Xantia if that helps.

I've seen the removable discs in the centre sphere regulators being opened out more by a precision engineers
to good effect on a very early G reg V6 manual. I'd never faff about with the corner spheres but can see the
virtue in altering the centre spheres as these are the true provider of the floaty ride. Cx spheres on the corners
IS DANGEROUS as I witnessed during my pal's 'experiments' on his car...

You never know, the ride may be quite good on the car off Paul anyway!!

The centre spheres don't have any dampers, the damping orifaces are built into the hydractive valve block. The orifaces are 1.25mm.

Rear spheres are nice and soft but the fronts a little firmer...

Ive experimented with BOTH over pressure and centre hole opening... both working to satisfaction.

The over pressuring for rears were great fun indeed. I had them fitted to the rear of my first Xantia TD.. the result was a rear end that was soooooooo soft and floaty just lifting the clutch would have the rear end right down on its stops. I had to adjust the rear height to slightly compensate.. that was fun.

Then I have sucesfully opend centre holes up with a 1.1mm NEW drill bit holding the sphere upright this too also made a nice soft ride from the spheres.

These were to my OWN cars! Never to a customers car at all..!

The reason i asked this question is on the Citroen dealer programme, the fronts are listed as 70 bar and the rears at 40 bar...these must have been the accumulator and rear centre

Wasnt it the case that the higher the pressure rating is the firmer the ride is or the other way round?

No the more pressure the softer it gets... hence spheres going hard over time as the pressure drops...

That said then Paul, how much difference would it make fitting accumulator spheres on the front corners? its a 20 bar increase over whats listed here so i presume it would render the front end unmanageable?, but there is no other difference other than the pressure rating is there?.....

There's plenty of difference.

Accumulators are undamped; your car would hop down the road like a 'roo at the first sign on a bump. Registration KAN6A?

I personally ascribe far more effect to the changing of gas pressure, than enlarging of the centre hole. Much more oil flow occurs through the damping washers/orifices than through the bleed hole. Given that you want to noodle about with this, it would be better to cosy up with a regasser and get pressures adjusted on the same spheres, than to rely on out-of-the-box items being all they claim.