I've been stymied to determine why some cantilever brakes and/or brake pads cause front forks to shudder sometimes violently and it doesn't seem to make a difference whether the forks are carbon, aluminum, steel or titanium.
I've used cantilever brakes on some bikes since the 60's and I don't remember this being a problem then. It is hard to believe that it is a fork problem since the forks of that era where not especially strong. I suspect it is caused by the brakes and/or pads. In one case, I solved it by using a softer brake pad that were guaranteed not to squeal. The pads wear out quickly during the cross season but they never squeal (all right, almost never).
I'm wondering whether some of the newer cantilever brakes are able to apply too much force. Even though the old Mafac cantilevers were better than their center pull brakes, they were no match for today's dual pivot brakes.
Del Mar CA