Before I dive into this question I should introduce myself as the owner of three Merckx; everything from a commuter Corsa Extra to a TI-AX flyer (the middle ground is held by an MX-Leader in Motorola team colors). I got started with the Ti bike about 5 years ago and realized that in 30+ years of riding nothing had either fit me as well or handled as nicely as the TI-AX. So here I am.
My question concerns the Corsa Extra. I have not been able to find any bulk brake cable housing that will fit in the internal tube through the top tube. I suspect that it takes something smaller than 4.4 mil and as far as I know only Campy produces a housing that small. As I mentioned above, this is my commuter; set up with a 7-speed DA group and I'd rather not spend a quarter of the value of the bike on cable housing. Any suggestions would be welcome.