How often do you change the spheres?

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

User avatar
osx
Posts: 541
Joined: 08 Jun 2013, 20:09
x 5

How often do you change the spheres?

Post by osx » 02 Jun 2019, 00:19

Is there an official recommendation when to change the spheres?

User avatar
GiveMeABreak
Forum Admin Team
Posts: 16912
Joined: 15 Sep 2015, 19:38
x 1571

Re: How often do you change the spheres?

Post by GiveMeABreak » 02 Jun 2019, 01:05

Officially for an X7 they last a lifetime - but that depends on their definition of what a 'lifetime' is..... The newer spheres are supposed to be impervious to nitrogen leakage - and it has to be said the struts seem to give out before the spheres do on these. I'm still on my originals at 79k and the ride is still great.

As I'll only ever fit OEM spheres, and given their price, I'll be waiting until I need to have them done (unless I see a job lot on offer from a dealer :)

User avatar
xantia_v6
Forum Admin Team
Posts: 6730
Joined: 09 Nov 2005, 23:03
x 327

Re: How often do you change the spheres?

Post by xantia_v6 » 02 Jun 2019, 05:57

The multi-layer sphere technology was first used on some of the Xantia and XM spheres from 1997, and at 15 to 18 years of age those that I measured still had good pressure. I am still using a couple of 20 year old spheres, but don't currently have access to a pressure gauge to check them.

The failures that I have heard of have generally been sudden rupture of the diaphragm, rather than a gradual loss of pressure. The physical shape of C5 spheres was changed to reduce the incidence of these failures.

That being said, most of the multi-layer spheres on Xantias and XMs were changed for the short-life standard spheres much earlier, often in an attempt to cure some unrelated suspension problem, or as a misguided maintenance item.

User avatar
bobins
Donor 2016
Posts: 2581
Joined: 05 Jul 2012, 18:07
x 562

Re: How often do you change the spheres?

Post by bobins » 02 Jun 2019, 09:04

The average age of a car in the UK is around 8 years old. I don't know how that equates to what the manufacturers expect a car's 'lifetime' to be, but I expect it has quite a bearing on how long they expect a car to reasonably last :roll:

User avatar
GiveMeABreak
Forum Admin Team
Posts: 16912
Joined: 15 Sep 2015, 19:38
x 1571

Re: How often do you change the spheres?

Post by GiveMeABreak » 02 Jun 2019, 10:00

I just had an invite to come and 'have a chat' from my Citroen dealer as my car has reached its anniversary! It is 10 years old - so they obviously think 10 years is time for a change - dream on.

andy5
donor 2018
Posts: 344
Joined: 05 Nov 2010, 14:40
x 31

Re: How often do you change the spheres?

Post by andy5 » 02 Jun 2019, 13:21

GiveMeABreak wrote:
02 Jun 2019, 10:00
I just had an invite to come and 'have a chat' from my Citroen dealer as my car has reached its anniversary! It is 10 years old - so they obviously think 10 years is time for a change - dream on.

I wonder if my Xantia will shortly get such an invitation for 20 years.

The local Citroen dealer did a clutch a few years back, and they sent me a postcard a year or two ago suggesting a cambelt change, so I am on some sort of mailing list.

I'm trying to remember if this Xantia is on its 3rd of 4th set of spheres. Last changes were at about 190k fronts and 224 rears (now 246), and it's just starting to feel like the fronts are slightly different from the back, maybe again in a year or two. So my guess would be intervals of 60-80k for this.

Perhaps I could do the fronts myself for the first time, with whatever recommended suitable tool, didn't fancy grovelling underneath the back last year with a knee problem.

User avatar
Sloppysod
donor 2017
Posts: 523
Joined: 23 May 2015, 23:35
x 41

Re: How often do you change the spheres?

Post by Sloppysod » 02 Jun 2019, 15:21

bobins wrote:
02 Jun 2019, 09:04
The average age of a car in the UK is around 8 years old. I don't know how that equates to what the manufacturers expect a car's 'lifetime' to be, but I expect it has quite a bearing on how long they expect a car to reasonably last :roll:

I read in a magazine about 20 or so years ago that the life of a typical car is about 50,000 miles, which does not go far from the 8 years (50,000/8=6,250 p/a), and going on the fact that most car start developing faults around this mileage it is still not far out.

User avatar
white exec
Moderating Team
Posts: 4701
Joined: 21 Dec 2015, 13:46
x 631

Re: How often do you change the spheres?

Post by white exec » 02 Jun 2019, 15:46

I think it's time, as much as mileage, that sees classic (non-saucer) spheres lose their gas pressure. Leakage/diffusion is going on even when the car is stationary. Just possible that regular use actually slows down gas loss a tad, as system pressure is exactly balancing out tendency of gas to permeate the membrane. Prolonged lay-up offers no resistance, if system pressure drops to zero.

Agree it's loss of gas that hastens a sphere's demise. If kept regassed, even classic spheres can soldier on for years. Unfortunately, by the time ride has become noticeably lumpy, the diaphragm may have taken a battering. This particularly applies to the corner (wheel) spheres, where centre (hydractive) spheres continue to provide a soft ride, and only the firm mode (only corner spheres operating) goes progressively lumpy. Anything much less than 15bar leaves spheres vulnerable.

Only a sphere checker, or regassing kit (which allows pressure check), can head off guesswork or nuisance replacement. The latter kit costs approx €150, so can be weighed up against the cost of spheres bought 'on spec'. Saucer spheres are a different ballgame, as discussed.

andy5
donor 2018
Posts: 344
Joined: 05 Nov 2010, 14:40
x 31

Re: How often do you change the spheres?

Post by andy5 » 02 Jun 2019, 16:42

Sloppysod wrote:
02 Jun 2019, 15:21
bobins wrote:
02 Jun 2019, 09:04
The average age of a car in the UK is around 8 years old. I don't know how that equates to what the manufacturers expect a car's 'lifetime' to be, but I expect it has quite a bearing on how long they expect a car to reasonably last :roll:

I read in a magazine about 20 or so years ago that the life of a typical car is about 50,000 miles, which does not go far from the 8 years (50,000/8=6,250 p/a), and going on the fact that most car start developing faults around this mileage it is still not far out.

There's a difference between average age of cars on the road and typical life. One should be approximately double the other, on the basis that cars on the road are mostly spread across 0 to 15 years, with some being older, thus average 8 years.

I can't believe that 8 years or that mileage would be typical life nowadays. Even the infamous times of the 1970s British car industry might have surpassed that, or at least all the ones I had went well past 100,000, such as a Rover SD1 V8 reaching 15 years and 173,000 miles and perhaps forever the cheapest car to run that I'll ever own.