when you say "shaved" does that mean that the star marked tyres actually come new with less tread on them than a "standard" tyre?
if thats the case then fitting a pair of part worn standard tyres would have the same effect wouldnt it? :blink:
[/quote]
There's a lot of 'guff' on the internet about this sort of thing and I'm just going to add to it.....
AFAIK the Star marked tyres are quite simply made to a specific rolling radius, so in theory a 255/40/19 star marked to fit an X3 will actually be physically the same rolling radius as the 235/45/19 which goes on the front. These tyres will be different physical sizes to tyres available with the same sidewall markings that aren't star marked.
What I can confirm is that they're not 'shaved' they come straight from the factory just like any other tyre. So, no it's not like fitting part worn tyres.
[quote="X5Sport"]...It only applied to staggered set ups on BMW cars as the tolerance in terms of different rolling diameter is supposedly very tight and can cause 'wind-up'.
I would have expected the system to cope, but the difference of a standard over a '*' marked can be as much as 23-25mm on the rolling radius front to back.
There are different versions for all sorts of cars such as
MO for Merc
AO for Audi
VO for VW
N1, N2, N3....etc for Porkers
[/quote]
Speaking from experience on this one. My X3 had three different brands of tyre with varying wear and a change to star marked Pirellis cured the problems.
The staggered tyre issue is well known on X3s. This is the first post I've seen of it happening with an X5.
The problem is simple, different tyre sizes front to rear will mean the transfer box is constantly being wound up as each end of the transmission is trying to turn at different speeds. Some systems - the Calibra has been mentioned, I've also seen the TT having problems - are particularly sensitive even to tyre wear on all-square set ups.
From doing some research I think that BMW attempt to overcome the problem by getting the tyre manufacturers to make the sizes that fit on staggered wheels to be the same rolling radius. It's my guess that Porsche are doing the same as the Macan is going to have staggered wheels too.
Have a quick google for X3 transfer box and you'll see what I mean
