Whenever my brakes start squealing, I know it's time to reapply (liberally) a coating of chicken fat to the pads, the rims, and just for good measure, the tires (acts as a preservative).

Keep in mind that this stuff is not available for retail purchase. If you don't want the hassle of rendering it yourself, you could make a friend in the bike assembly dept. at your local wally-mart. They go through this stuff by the gallon, though I don't think they use it on brake pads, just cables and bearings.

Actually I agree with most of what's been posted here. I know that you said your cantis don't provide a toe-in angle adjustment, and while that's possible, I think it's worth double-checking. The washers on the mounting bolt (the bolt with the hole through it for the pad stud) typically have cylindrical surfaces facing the canti arm (front and back of the arm). They look like regular flat washers at first glance, from the outside, but once you loosen things up it's easier to see that they have these curved surfaces. So, when you tweak your toe-in, you are moving the pad AND the mounting bolt.


I hope this helps.

Sheldon Brown has a number of pages dealing with cantis and their adjustment, including a very interesting discussion on the physics of different canti geometries and setup options.


Also, +1 to the Park link.