[Alscoob]

Originally Posted by hdaskalov

Hello. I just want some advice about the tires. The car came with Michelin Primacy 3 ZP runflat from factory. When the worn out last summer I decided to change to non runflat tires without the BMW star homologation. I bought Michelin Pilot Sport 5 with the same size as original tires were - front 245 45 19, rear 275 40 19
The difference of comfort between runflat and non runflat tire was not noticeable. I suggest this is due to the Air suspension of the car.

The problem was that the front Michelin Pilot Sport 5 were 2 cm lower than the rear and the size didn't match that of the original tires. The xdrive error appear and had to sold them. Now I am considering between Michelin Primacy 3 runflat (which the car originally was fitted) with BMW star and Pirelli P zero PZ4 non runflat with BMW star.

The attachment is photo of Michelin PS5 and the tire difference between front and rear.

Blimey, that's bad. If you input the sizes here https://alloywheels.com/tyreCalculatorResults2

It shows just a 0.07% circumference & 0.5mm difference in diameter. Guess they were both manufacturered at the opposite extremes allowed under the ETRTO -2.5% and +1.5%