What have you been doing with your spheres?

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What have you been doing with your spheres?

Post by BX Bandit » Wed Jan 17, 2007 3:28 am

I have been wondering what people have tried with regards to changing/modifying spheres on their BX.

Due to reccomendation, I fitted some XM V6 spheres on the front of my TD. I assumed it would be a very hard ride but its not actually that bad. The ride feels more like the 16v...stiffer and well composed but not very floaty.

On the rear I drilled the centre bore to 1.5mm (originally 1.1)..the ride is noticeably softer and much more floaty.

Not the best combination but it will do until I have the readies...er...ready to buy the spheres I want.
So, any opinions/suggestions/tech input??
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Post by adamskibx » Wed Jan 17, 2007 10:05 am

I would have thought that hard spheres up front and soft at the back will exagerate understeer. As I understand it, roll angles are kept under control by the stiffness of the anti-roll bar, and of the suspension. The car is rigid, so whichever end is controlling the roll the most will have have the greatest weight transfer to the outside wheel on a corner, reducing grip. Also, the harder spring rate means the front is more likely to get knocked off course by bumps. I would say you want the back of a BX comparatively softer than the front to balance the handling and reduce its natural understeer. Indeed, the 16 V spheres and roll bar combination improves on the standard cars tendancy to understeer.

tim leech

Post by tim leech » Wed Jan 17, 2007 10:53 am

I had 5 new ones on my 16v in december (thanks Ian) I replaced them correct ones and find the ride firm but with good handling.

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Post by docchevron » Wed Jan 17, 2007 1:04 pm

The possibilities are endless!
Really depends on what you want from the car!

I'm still playing about with the ultimate setup for me on the TD, or at least I will when I've stopped the front end groaning like a hooker on overtime.

I'll keep you in the loop of what happens Bandito!

16v ARB's work well!!

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Post by Stewart (oily!) » Wed Jan 17, 2007 5:21 pm

I have TZD spheres on the front and Valver ones on the back, it still doesnt handle as well as my old GTI/TD though? maybe its riding a little higher? or something.
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Post by tom » Wed Jan 17, 2007 8:13 pm

I just fitted a new set of the correct spheres to my TZD estate and I reckon that it shows that Citroen know best!
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Post by BX Bandit » Wed Jan 17, 2007 8:13 pm

It wasn't really an intentional set-up, I'm playing around really.

With the stiffer front end, weight is transferred more quickly onto the outside wheel. The quicker the weight is transferred, the quicker the outside wheel gets grip turning into a corner and so less understeer. With the old 'saggy' spheres, you could sense the delay between turning the steering wheel and feeling the weight of the car shift. So with the stiffer spheres, there is less understear...much more like the 16v. I haven't really pushed the car but I think the soft rear end will create an unbalance under duress.

As Doc says, there will be alot of combinations depending on wether you are after a floaty ride or a sporty one. I'm keen to have a floaty ride for the TD. A 16v ARB should reduce that understeer without hardening the ride so would be a good way forward.

I was surpised that the XM spheres were not much harder than they actually are considering the central bore diameter is 0.6mm compared to the 1.8 that is standard for n/a diesel spheres....
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Post by AlanS » Wed Jan 17, 2007 10:12 pm

Be real careful trying to soften up the front.
It's a long story (that several on here have heard before..........many times) :-({|= but we once bought a wreck of a burnt out 16V. I had spoken to people who had driven it prior to the bonfire and all described its ride as "unstable" even when compared to tin spring cars.
I had cause to 'borrow' the front spheres whilst new ones were coming through and found at 110kph on gravel as I approached a corner and had to stand a fraction harder on the brakes than usual on the approach, that it sank too far at the front and "fishtailed" the rear.WTF?
As I was aware a problem existed it was no real big drama, but had it happened unexpectedly, could have been extremely dangerous.
IMO, Citroen has millions to do R & D and we only have a couple of spheres to experiment with, so I also agree, Citroen knows best. [-X


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Post by Kitch » Wed Jan 17, 2007 10:59 pm

Because I'll be fitting different alloys with lower profile tyres, I'm toying with the idea of GTi/TZD spheres to soften the ride a little to compensate.
If its too floaty, the logic was that I could always get them regassed to 16v specs and 16v spheres aren't the easiest to find these days.

Its not like the 16v has little body roll either....it rolls pretty much the same as most BX's, its just ever so slightly more reluctant to do it.