A Different thread about Runflats.

[Osinjak]

gizlaroc said:

This has been discussed ad infinitum on BMW forums for over 10 years since run flats first came out, so many people get excessive wear on the inside edge, and the moment they swap to regular tyres it stops.

I have also had 7 BMWs on runflats and only the E91 335i on Michelin Zero Pressures have worn evenly.

The 5GT was horrific for it, really, really bad. Swap of tyres for proper ones and perfect wear.

So as far as I am concerned it is you talking cobblers. Your experience of one car doesn't really give a very balanced view and even the tyres makers and BMW have said it has been an issue, it is getting better with later generations of both tyre and car, but has been a serious issue on some cars and put many off BMWs as the wear rate on some of the bigger cars has been ridiculously quick.

Cobblers. I don't doubt what you say and I'm actually with you but to suggest ALL E9x suffer from it is, well, cobblers. One car does not support a theory anymore than yours does but your assertion that ALL E9x cars suffer from it is wrong because mine didn't. Before you go off on one, I think I'm in the minority and perhaps 'got lucky' and so support your viewpoint but it's just daft to say ALL do when they don't.

[t400ble]

Madness.

I'd have honestly looked at the tyre before driving away.

[Simes205]

Our e91 msport wears its tyres out unevenly, inside edge just gets knackered. One of our rears looked like the ops although it wasn't right through.
Tracking, camber and castor have all been checked and checked again.

[gizlaroc]

Osinjak said:

Cobblers. I don't doubt what you say and I'm actually with you but to suggest ALL E9x suffer from it is, well, cobblers.

You have a really nice way about you, were you bullied at school?

Osinjak said:

One car does not support a theory anymore than yours does but your assertion that ALL E9x cars suffer from it is wrong because mine didn't. Before you go off on one, I think I'm in the minority and perhaps 'got lucky' and so support your viewpoint but it's just daft to say ALL do when they don't.

It is one of the most discussed things on the BMW forums, 3 series, 5 series, 1 series, 7 series, X series forums, all the same and always the same results.

Yeah there are exceptions, as I said, my 335i touring on Michelins were wearing evenly, well the inside was slightly wearing quicker than the rest, but nothing to really worry about, but in general the main cause of this is run flats, not geometry, not under or over inflation, but the fact the car is on run flats.



I just think it is bad advice to tell someone to adjust pressure or change geometry and it will cure it, it doesn't, swapping for proper tyres will cure it.

[Osinjak]

Frankly, I wince when I'm behind an X5 and spot the camber. It must be hideous replacing a full set on one of those bad boys. I've found the RFTs to be incredibly sensitive to pressures, my first set did wear badly but my second set have been fine since I got the tracking done (unrelated to tyres, biffed a kerb) and maintaining the pressures. Still, it's a poor show all round that this is occurring in the first place given the tyres are so bloody expensive.

[gizlaroc]

Osinjak said:

Frankly, I wince when I'm behind an X5 and spot the camber. It must be hideous replacing a full set on one of those bad boys. I've found the RFTs to be incredibly sensitive to pressures, my first set did wear badly but my second set have been fine since I got the tracking done (unrelated to tyres, biffed a kerb) and maintaining the pressures. Still, it's a poor show all round that this is occurring in the first place given the tyres are so bloody expensive.

I think the problem with BMW is they have always had an aggressive camber, and this worked on regular tyres and they didn't adjust it for runflats. If you adjust it out you do then loose some of the mechanical grip at the rear when pressing on.

As the run flats get better I am sure it will be less of an issue.