rear brake choices on a Trek 520
 

I am putting together a new Trek 520 that still has the original Avid V-brakes installed. I have a full fender and a Tubus Logo rack also on the rear. The Logo and the rear V-brake don't mix on the Trek 520 because the left top support arm on the Logo impedes the metal brake cable enclosure from clamping the left side of the V-brake to the rim, as it should.
Has anyone else had this problem and if so what kind of brake works best with a semi cluttered set up like this? Caliper, Cantilever?
Thanks!

I would look to modify the rack arms before replacing the brake. V-brakes levers have a long cable pull and don't work well with traditional canti's or calipers.

I had the same problem with my 2007 Trek 520, but got around it by lowering the contact point between the brake cable and right arm (see photo). It's just enough (literally a millimeter) to prevent contact between the Tubus arm and brake system. Hope this helps!

http://files.schwiiz.org/images/2009...ek520Brake.jpg♦

I too had he same problem. But, as chrisch's picture shows, I resolved it by using the fittings in the inside of the seat stays rather than the ones on the outside. You could probably also put a slight bend in the Tubus rack mounting rods (they are solid steel).

these might work

http://www.canecreek.com/images/other/brakes_dc5.jpg