MTBaddict

Do Shimano BR-R550 brakes rotate on the canti post or do they have an internal bearing/bushing on which they rotate (like Paul's Touring Canti, Shimano XT V-brakes, etc.). I am concerned about long-term wear on my canti posts because they are not removable (welded).

dabac

There are those who claim having seen cantis that rub against the post, but I've never come across one. Not that I'm a professional mechanic, but I do spread my tinkering far and wide...

MTBaddict

Most cantilever brakes that I have seen are made with a brass bushing that rubs against the steel canti boss. Normally, they do not have seals to keep the grease in and the contaminants out. Even some expensive canti brakes for cyclo cross go this route to keep the weight to the minimum. I wouldn't run them on a touring rig.

desertdork

After checking a new, unmounted BR550:

The canti arm rotates on a bushing; it does not pivot on the
post itself. The spring anchor stud is integrated with the
bushing. Once this stud is inserted in the hole adjacent to
the canti boss, the bushing is essentially fixed in place and
will not rotate against the canti post. It would seem that
greasing the post serves to guard against rust/corrosion, not
for protecting against abrasive wear. "Seals" wouldn't do much.

MTBaddict

That's exactly the information I needed. I suspected such was the case by checking photos of the BR-R550, but I needed more certainty before putting my money down. Thanks!