Tyre Stability Problem E46 330D with GY Eagle F1 gsd3

Hi,
I have a E46 330D SE Touring (MY2000). I've been running it on 225/45ZR17 Good Year Eagle F1 GSD3 now for about 40,000 miles but the rears needed
changing as they were almost illegal, however the front tyres were fine. I decided to keep the front tyres and install 2 new tyres of the same type exactly on the rear. So thats what I did, and after driving out of the tyre shop I noticed that the car's handling had changed dramatically. The car was handling brilliant up to the tyre swap and now it's down there with the worst ever handling car I've ever had!
I thought that it might be me being oversensitive at first so I left it for a while in the hope that it would improve. I've checked the tyre pressures twice and tried the car at the low end and high end of whats acceptable based on the door sticker tyre pressure guide. I've also checked that the wheels are on tight and it's been in to a BMW specialist who cannot find any fault with it. However, the car handles like a 'boat' and feels dangerous at speed. It tramlines a lot and the rear of the car wants to steer on its own and needs constant attention and correction of the steering. Often I head over the while lines and need to pull the car over. Its really quite bad on the motorway!
Has anyone any idea what may be causing this and how I can get the fault identified and remedied ?
I am taking it back to the tyre shop hopefully today to get the tracking looked at and see if the tyres may be at fault.
Thanks for all your help
Marc
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You are probably going to have to get new front tires, too. Try this: swap the fronts for the rears. If it doesn't tramline as much, either leave the new ones on the front, or get another set.
I have a 330xi with that size summer tires (actually, they're the US's 325i sport package wheel/tire), and when I put on my summer tires this spring I had a similar experience. I swapped them around so that the best (least worn) tires were on the front and it was magic. I'll be sure to mark them this fall so that doesn't happen again.
Floyd
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"M C" wrote

You've probably checked this already, but if not, make sure the tires are mounted the correct way, since they're directional.
Brand new tires will not feel as quick and responsive as worn out ones due to tread depth. More tread - more squirm. Also, new tires need a few hundred miles to break in - that's when all the manufacturing greases wear off. But none of that would explain such a dramatic change in handling like you described. Something else is going on.
Cheers,
Pete
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Thanks for your input.
I went back to the tyre shop and they swapped the front with the rears so that the new tyres are now on the front and the worn ones on the rear.
The car is far better, and immediately back to it's predictable ways. I also spoke to a friend of mine at the weekend who claims that new tyres should normally be fitted to the non-driven wheels and says that there's some explanation for this. (He drives a Westfield). To complicate matters further I had read somewhere else in the past that with a rear wheel drive car to put the new tyres on the rear. It's difficult to know what to do for the best! Maybe it's dependent on brand and tread design ? Pretty weird that such a noticable change in handling can be caused by fitting new tyres. I'd go as far as saying that the car actually seemed quite dangerous for the duration that I was trying to get this sorted out. Anyway, I'm happy again now.
If anyone has a scientific explanation for this anomaly can you please oblige and add to the thread.
Thanks
Marc

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matters
for
tyres.
the
again
I've no doubt it has something to do with slip angles being greater with new tyres than part worn. I'll leave it to someone else to expand on that theory. :-) Mike.
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Always new tyres to the back, no matter what wheels drive the car. The AA (major motoring organisation in UK), Michelin, Kuhmo and Yokohama all state this, and that's just what I could find in two minutes of googling! Always to the back! :-)

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"zerouali" wrote

Well, the OP did just that, yet experienced major handling issues until he put the new tires on the front. Personally, I'm still puzzled by this, unless he had some sort of an alignment issue.
Cheers,
Pete
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I'm none the wiser as to why the OP has the problem he did, but when it comes to tyres I tend to trust the people who make them, they usually know best!
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he
In a general sense, yes. In particular, not necessarily. Mike.
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Here's a link : http://www.michelin.co.uk/uk/auto/auto_cons_bib_pqr_neuf.jsp

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