Have you ever worried about this with your car?
There are lots of different makes of car tyre, as long as they meet the appropriate BS and you are using the right type of tyre you won't have any insurance issues.
Bikes are no different.
Regarding warranty issues I don't think BMW are going to reject a warranty claim because you fitted a GT instead of a TRAIL. Don't forget that the tyres themselves are not covered under the warranty as they are consumables.
The reason BMW will only fit approved tyres is that in the event of a problem with something they supplied the lawyers can pass liability down the line.
There are lots of different makes of car tyre, as long as they meet the appropriate BS and you are using the right type of tyre you won't have any insurance issues.
Bikes are no different.
Regarding warranty issues I don't think BMW are going to reject a warranty claim because you fitted a GT instead of a TRAIL. Don't forget that the tyres themselves are not covered under the warranty as they are consumables.
The reason BMW will only fit approved tyres is that in the event of a problem with something they supplied the lawyers can pass liability down the line.
