Ok... so I'm bored at work... assuming a 32H rim (starting with no holes), that's 30 possible holes. Taking out a 25mmx30mm section from each, say 3mm thick (possibly a bit high but you get the idea) and using the density for aluminium of 2700kg/m^3 means that the total mass of metal removed would be 182.25g. So I guess 100-200g per wheel isn't actually that far off!! Sorry Rowan edit: Oh yeah, the bike! For some reason I really like the look of the Boxx and Vince's looks like one pretty dialled machine! Sorry if this has been answered somewhere but is the frame mod rear spaced?