Thread: Half rfts
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      01-27-2013, 05:24 PM   #33
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Drives: BMW F11 535i Touring
Join Date: Mar 2007
Location: Scotland, Highland Region

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Originally Posted by Eelesy24 View Post
Why not believe it?

For auc yes you need to put the vehicle to standard as you would if it had any non standard accessories. But this isn't for auc this is for an individual customer, disbelieve me if you like but that was the response from BMW.
I'd be very surprised if this is the official view of BMW.

For one, they are going against the advice and guidelines of the tyre industry.

British Tyre Manufacturers’ Association
Mixing SSTs with standard tyres
The handling and performance characteristics of SSTs are different to those of standard radial tyres, and so they should not be intermixed on a vehicle, i.e. all four tyres should be similar in structure.
Then there is the individual advice from the tyre manufacturers themselves, now apply industry advice to the insurance companies, and their knack of seeking get out clauses. Such as:

Pirelli does not recommend mixing run flat tyres and standard tyres on the same vehicle, even if paired in axle sets.
From Continental, in a list of WARNING! notes

It is extremely important to keep the following in mind:
An SSR/standard tyre mix should not be fitted on a vehicle – not even axlewise. (In isolated cases a standard tyre can be temporarily mounted on a vehicle otherwise equipped with SSR tyres. It must be pointed out to the driver, however, that the standard tyre has no runflat properties.)
We could find many more quotes.

There is added risk, and if the advice is clearly spelled out, as it is, I can't see BMW going against that industry advice. I'd imagine any reply from BMW had not passed the legal department before release.

If they have made it their official policy, it can be open to challenge if and when someone chooses to. Say if 'incorrectly matched' tyres are viewed as part of the cause of an accident.

I wager it not an 'official' BMW statement.