Xantia Estate Handling

[Mandrake]

This question might be one for you blokes, as there are that many more wagons floating about in the UK. Regular 6 sphere Series II is the one in question...

I've dropped tyre pressures down to factory placard levels (33 front/30 rear unladen) on the OEM size 185/65/15 rubber. Previously had them pretty high (44/42) for economy and accuracy of feel.

What I've found, is that at the lower pressure there is more control/graduation to how much the front scrubs out and chronically understeers, but it's happening at comparatively low speeds. Does this represent what others have found on similar sizes/pressures of tyre? Rubber is Toyo Teo front, ancient Olympics on rear. The kind of speeds I'm talking about are around 15km/k into a hairpin, or 35km/h into a tight 90° corner.

Ok as soon as I saw the words "chronically understeers" I know you have a problem. A properly shod Xantia is not a chronic understeerer by any stretch of the imagination.

Two things - one is that the standard model does NOT handle as well as a Hydractive 2, the difference is quite noticeable, we have both so I've driven both quite a bit. There is no doubt the Hydractive 2 handles better. (And rides better too) On really tight cornering the standard model wont compete as it will roll too much.

The other main thing though is the tyres - 185/65/15 is undershod if you are trying to get handling performance out of a Xantia, plus I have no idea what the characteristics of those tyres are but if they are scrubbing in the corners they don't sound very good.

To give a comparison my Xantia (Hydractive 2) came with 185/65/15 "Champiro" tyres on it, and they were the biggest load of c**p I've ever come across. Even with full tread on them they squealed and scrubbed around tight hairpins or hard cornering and understeered / ran out on tight corners quite badly.

After about 3000Km (of admittedly spirited driving) the shoulders were completely worn off the front tyres.

I went to 205/60/15 Michelin XM1 and its like driving a different car. No real understeer to speak of, very close to neutral balance when you push it hard, no squealing or scrubbing of the front tyres and LOADS of grip in tight corners especially in the Hydractive 2 "sport" mode.

When I was testing a gadget that can measure G-forces a month or so ago I measured what it could do in a tight hairpin (120 degree) corner at about 30Km/hr and it was measuring 0.93 G's, and thats without the tyres squealing, nothing wrong with that (and no understeer - perhaps a touch of oversteer or self rear steering if anything)

I got over 30,000Km of hard driving out of those front tyres too, I like to chuck it around corners, I've just put a new pair on now.

Also, I'm running them at the standard pressures of 33psi on the front and 30psi at the back - I experimented a lot with the pressures when I changed the size of tyre but ended up coming back to the standard pressures.

Is it mainly a function of wheelbase and suspension geometry, this way it forces you to slow so much for corners?

No I think it's mainly a function of tyres that are poor and/or too small for the handling you're expecting. Go up a couple of sizes to 205/60/15 and to a better grade of tyre and it will probably be like driving a different car.

Can oversteer be safely generated in a non-Hydractive Xantia, and if anyone has managed, what were the tyres/pressures/techniques?

Explain why you would want to generate oversteer ?

With the comparatively slippery front end, I'm reluctant to power hard out of a turn in case it ploughs straight ahead and just gives me a bag of chassis/torque reactions to digest.

Again, "comparatively slippery front end" sounds like poor tyres to me, I wouldn't classify a Xantia that way at all.

Yes, I know it's not a Skyline or Lotus Seven, but it is a fun car that invites spirited driving. Just that I am keen to hear some seasoned opinions on where the limits really are. No point pushing it to levels of stupidity (or embarrassment, if one is more fortunate).

Thanks, Adam.

The grip limits of the Xantia with good tyres are surprisingly high - like I say on mine I measured 0.93G's of lateral force in hairpin cornering, although a non hydractive model may not do as well.

(disclaimer - don't test G forces on public roads )

Regards,
Simon

[addo]

I can't wait for the four wheel drifting stories either!

That aside, to answer your question Simon... Oversteer is mainly something I'd like to see/understand in this car as a controllable aspect. Doesn't mean it would be used necessarily, but as perhaps the quality which could save a corner or evasive manoevre, I feel knowing it has a place. Did you fit the 205s onto Activa or "Le Castellet" style rims; wondering because mine are only 5.5 wide (unlike Activa wheels)?

Thanks also to Pete Wood for a great plain-speaking description, which made Xantia driving sound like even more fun.

Regards, Adam.

[Xaccers]

Even with "metal showing" bald tyres on the front I've not had Cassy understeer.
They were god awful continental low rolling resistance ones, that lasted 4 months and mad a hell of a squeal going round roundabouts unless I pushed their pressure up to 35psi

[Old-Guy]

With a combination of old cheap tyres, you shouldn't be surprised it handles badly!

The 5 'design' parameters for cheap tyres are:
- minimum cost,
- legal requirements of the intended market,
- minimum cost,
- reasonable tyre life at minimum cost,
- minimum cost.

Non-essentials like grip, ride, handling, and road-noise don't come into the equation. R&D? It cost money!

Tyres deteriorate with time, heat and sunlight.

Citroen and Michelin have had a close working relationship for more than 60 years, so it should be no surprise that Xantias drive well on Michelins. The factory fitted Michelins to our 1995 1.9Td estate - 3 of them, including the unused spare, were still on the car when I bought it 11 years and 67,000 gentle miles later! It hurt to replace tyres with that much tread on them, but at that age they were an open invitation to a serious motorway accident.

On newish Michelins, at the recommended COLD pressures, and with recently overhauled hydraulics, it can be chucked around with surprising verve - even in the wet. Handling towards the limit is totally predictable and safe: mild power understeer, neutral on a trailing throttle, suddenly lifting off in a sharp corner tightens the line with no more than an aggrieved twitch of the chassis.

The only downside of the Michelins is the loud squealing on every turn in multi-storey car parks - at walking pace it sounds like a boy-racer on fat tyres!

[pete_wood_uk]

loud squealing on every turn in multi-storey car parks - at walking pace it sounds like a boy-racer on fat tyres!

We digress, but since when has that ever stopped us on this forum.

I was driving the C5 round a shiny-floored multi-storey a week or two ago, and being embarrassed by the horrendous squealing and scrabbling noises. As it happened, I ended up parked near one of the turns, and had to stand and wait by the car for a few minutes, so I watched the cars going round the (uphill, right-hand, full-lock) turn. The differences between manufacturers were enlightening. Most BMWs, for example, tracked round the corner with almost no fuss. Ford Focuses tended to squeal a bit, whereas most offerings from the PSA camp (Peugeot, Citroen) were visibly hopping and skipping one or other front wheel sideways across the concrete - the geometry is completely out and the wheels weren't tracking the correct arcs.

I presume that this is because the geometric relationships of oily bits needed to get wheels to track successfully at full lock aren't *necessarily* compatible with chosen suspension geometry and layout, not to mention front-wheel drive shafts and CV joints, so the engineers presumably think "Oh, bollocks to it, it's near enough, it'll do" and accept that it's near enough for the first critical few degrees of turn either way and don't worry about it too much at the extremes of lock. The BMW designers, having no front driveshafts, and being German, may have an easier time in getting it right?

All the above is speculation. Anyone know anything?

Pete

[rowanmoor]

Isn't it more to do with the McPhereson (sp?) struts than anything else. I bet the C6 and C5III don't squeal (both having double wishbones), and the CX certainly won't.

[jeremy]

Many BMW and Mercedes have strut front suspension.

[Xaccers]

Cassy's rear has been a bit bouncy and rattly lately (exagerated by having my toolbox in the boot) so I checked the tyres and they had about 2mm left on them.
Popped over to costco and had michelin energies fitted to the rear, so I now have them all round.
Much smoother and roundabouts I used to take at 30 I can now easily do at 40 (that's with my toolkit and 60L of veg in the boot too)


Lets see if they last more than 4 months

[addo]

I managed to get the front a little sideways on Thursday afternoon again, through a chicane-esque thing at 50 (what's that - 31MPH?). Time for a tyre temperature probe.

Regards, Adam.

[myglaren]

My daughter sold her Xantia, although she loved it, mainly for the space inside (three kids in the back, two in safety seats) the ride and the general feeling of a 'solid' car.
She soon dumped it when it broke away on a roundabout at low speed, twice.
She had the suspension, steering and tracking checked and all was pronounced OK.
My contention that it was down to unsuitable tyres but she wouldn't drive it any more and so it went.*

I am guilty of using cheap tyres in the past, partly as where I work there used to be hundreds of screws on the ground (no not a prison) and I got through tyres quite rapidly as a result of many punctures.

That isn't the case any more and a couple of weeks ago I had a pair of Kleibers fitted to the front wheels, after reading many personal experiences on this and other forums about tyres.

I can't say that I have noticed any huge differences in the tyres and handling (other than the cost ).

I do chuck it around roundabouts and corners a lot though. Small roundabouts at 30 (don't slow down, just a blip on the loud pedal to drag it through. Big roundabouts a 40~50 up to 60 depending on the size/visibility/amount of traffic.
Ordinary corners (90° junctions) at thirty.

I will admit that this is principally to spoil the day of the (-expletive removed-) who come thundering up behind me when I am proceeding at the legally required 30MPH and visibly gnash their teeth as their progress is impeded. On approaching a roundabout they will reduce their speed to barely more than a 15MPH crawl while I carry on at the same speed. The look of horror on their faces is priceless as they are left dozens of yards behind, then of course they have to make up the difference when the road straightens, only to lose it again on the bends.

I accept that this is a pretty childish exercise but it does please me that a clumsy looking heap like a C5 estate can whip around corners with aplomb and leave the chavas in it's dust (no smoke here, oh no!).

*replaced with a pair of 525i's. She slid hers off a roundabout in a very dramatic fashion and refused to drive that again too.

[Xaccers]

I will admit that this is principally to spoil the day of the (-expletive removed-) who come thundering up behind me when I am proceeding at the legally required 30MPH and visibly gnash their teeth as their progress is impeded. On approaching a roundabout they will reduce their speed to barely more than a 15MPH crawl while I carry on at the same speed. The look of horror on their faces is priceless as they are left dozens of yards behind, then of course they have to make up the difference when the road straightens, only to lose it again on the bends

You do that too?

You're definitely right about the tyres making a difference to the handling and how dangerous a bad set can be on the rear.
Cost doesn't always play a factor though.
The continentals I had on Cassy were nearly £80 each, lasted only 4 months and squealed like buggery going round bends at anything over 20mph.
First set of tyres I put on her were about £40 each (Arrowsomething), lasted a year (longer for the rears) and gripped the road like superglue.

I think on my first Xantia I used to fit £25 Kumho's and never had a problem, changed to conti's (I think about £50 back then) and had the back slip on a bend and a couple of weeks later span off doing 30mph (ok the spinning was caused by the n/s/f wheel clipping the bank because the road wasn't quite wide enough to recover from the spin the back slipping out was trying to put me in).

[XantiaMan]

My TD had Continental PremiumContact on the rear and they were superb never once did i doubt their grip or give me cause for concern. Wet handling also was great and i got 30k out the back, just a bit low on the edges now but if i could afford them would have no problems in buying the same again.

As for four wheel drifting, it has to be pushed (Activa) and it tends to start around the point the front end will understeer but it can still be adjusted by more or less power.

[addo]

You do that too?

We all do!

To see if tyres were doing anything funny, I picked up a thermocouple probe for my mouldymeter. Pressures were set to PSA recommendations.

After 45 minutes of normal suburban roads, temperatures were pretty even across the treads except the inner margin showed about 2°C cooler. Fronts were hotter than the rears by about three degrees with a light payload.

Bumping the pressures by four pounds might be next step, to see where temperature spreads go. Based on the comments and experiences of others, the interim feeling is that I'm probably driving it near the practical limits for this combination of rubber and roads. Slowing down might be a safe and cheap solution!

Cheers, Adam.

[addo]

Just want to "bump" some questions that others might be able to help with:

My rims are 5.5 wide, and are recommended for the 185 width tyres.

What will happen if I go wider/lower profile, as to the 205 used on Activas (albeit with their 6.0 wide wheels)? Will the extra sidewall curvature on the narrower rims negate any real handling gains?

How do 205 go on a non-Hydractive car, in foul weather? Is there a significantly increased risk of aquaplaning, or losing the rear?

Thanks, Adam.

[CitroJim]

How do 205 go on a non-Hydractive car, in foul weather? Is there a significantly increased risk of aquaplaning, or losing the rear?

Never had a problem and we get plenty of the foul stuff here