poster's question relates to the height of the brake bridge on the seat stays. Given that the System Six has a fabricated rear end, it is possible to have variations in the location of the brake bridge in relation to the drop out. As I noted, on my size 60, the brake bridge will rub a 25 mm tire. Perhaps a change to a different caliper would help marginally, but on my DA 7800, center bolt is awfully close to the tread of a 23mm tire.
I'm surprised that Cannondale would have this much variation - but obviously they do. My CAAD has more than 5mm clearance to the seatstay and bridge, and 4mm with the brake installed. Also 4mm to the FD clamp on the seat tube.
All pictures with a 28mm Conti Gatorskin.
There's sometimes a buggy.
How many drivers does a buggy have?
So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.http://www.youtube.com/watch?v=GekiIMh4ZkM