road wheels:

Mavic Cosmic Carbone Ultimate: 1185 g
Mavic Ksyrium SL Premium: 1480 g
Mavic Aksium: 1855 g


track wheels:

Mavic iO/Comete: 1730 g
Mavic Ellipse: 1995 g
Cane Creek Endurance 85: 1791 g
Cane Creek Volos Track Clincher: 1766 g


mtb wheels:

Mavic Crossmax SLR Disc: 1520 g
Mavic Crosstrail: 1750 g
Mavic Crossmax SX: 1920 g


Anyway, you get the idea. I'm surprised that XC mtb wheels are lighter than most track wheels, and that track wheelsets tend to weight as much as freeride wheels. What demands of track cycling demand such strength in wheels? Or is it that weight is sacrificed in favour of a more aero profile? It's pretty clear why a disc/four spoke set would weigh more, but I'm a little confused by the Cane Creek Volos and Mavic Ellipse, which are basically road wheels with track hubs.