[legion]

There are two kinds of systems (that I know of) for monitoring tire pressure. One directly measures the pressure of the tires, the other basically measures how long it takes a tire to make one revolution and derrives the pressure from that. The first setup works regardless of tire size (my Silverado has such a system). The second system is very sensitive to tire size. I don't know which system your MB has, but it is conceivable that it does take a laptop reprogram.