XSeries-forum

Does anyone know if you can use the a Y speed rated tye instead of W.  The rest us the same for example 275/40 R20 106

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The general rule is that you can go higher, but never lower with the load rating.  ‘Y’ is higher so OK. 

The tyre pressure plate will tell you the minimum rating that BMW got the car type approved with.

[quote="X5Sport"]
The general rule is that you can go higher, but never lower with the load rating.  ‘Y’ is higher so OK. 

The tyre pressure plate will tell you the minimum rating that BMW got the car type approved with.
[/quote]Thanks......checked the plate and W is minimum.

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[quote="X5Sport"]
The general rule is that you can go higher, but never lower with the load rating.  ‘Y’ is higher so OK. 

The tyre pressure plate will tell you the minimum rating that BMW got the car type approved with.
[/quote]
Not sure I agree with this. There is no ‘minimum’ rating other than the general requirement that the tyres must be suitable for the load/speed they will be used at.

For example, the bmw supplied winter tyres will be H or V rating. That’s not because the law allows for lower rating on winter tyres and there isn’t a ‘winter type approval’. It’s simply because H and V are still entirely suitable for any vaguely legal speeds in the UK.

Incidentally, I’ve seen correspondence from Land Rover where an owner specifically asked whether it was ok to use lower speed rated tyres (they wanted to fit all-terrains which rarely come in high speed ratings). LR said they don’t specify a speed rating and it was up to the owner to choose tyres which were suitable for whatever conditions they would be used in.

He was asking about ‘summer’ tyres specifically, but yes winter tyres are a lower speed rating.  The BMW tyre plate lists all approved tyre sizes and load limits and speed rating, including winter ones - with their relevant minimum load index/speed rating (and the winter ones may well be different).

You need to read the plate to confirm the load limit/speed rating for the tyre size/type.  That plate is part of the type approval requirement.

My response covers all tyres, including ‘summer’. I used winter tyres as an example only.

The tyre plate refers, as you say, to the type approval - but this is nothing to do with the construction and use regulations which we have to abide by. The approval regulations state that the tyres fitted by the manufacturer must be rated to the maximum design speed of the vehicle at least. This is because bmw don’t know how you will use the vehicle so they must fit a tyre which covers all possible speeds. However, as the vehicle owner, you must meet the constructions and use regulations, not the approval regulations. The construction and use regulations make no demands on speed ratings (other than for goods vehicles - not relevant here) and simply state that the tyre must not be “unsuitable having regard to the use to which the motor vehicle or trailer is being put”.