According to this, the front style 63's (y-spoke) weigh over 18kg whilst the rears weigh just over 12kg?

Felgen-Katalog - BMW-Treff - der Treffpunkt fr alle BMW-Fans und -Fahrer

That cannot be right can it? The front is narrower for one, and for 2 that would just be ridiculous for the different to be so huge surely.

Got to be an error right? Anyone actually weigh theirs?