Please help much revered elders!
I have recently purchased a 1985 Raleigh Portage which has it's fair share of weird frame characteristics. The most frustrating thus far has been the cantilever bosses. The holes on most bosses for the spring to interface with are on the inside of the actual cantilever post, but on this bike the spring interface holes are on the outside of the post.
Because the tension adjustment holes are on the opposite side of the post from a normal brake boss all the springs I have tried result in extremely high tension levels when the brakes are installed. That is, if I can actually manage to install the calipers. The only way I have found to install a functioning caliper is to install without the plastic dust cap which protects the spring and forces the spring to remain inside the caliper itself. This lets the excessive spring tension bow out of the caliper without inevitably breaking the plastic cap.
I purchased the frame and wheels with no components, but have purchased the original Deore XT calipers for the restoration. I also have a slightly newer XT caliper that seems to work a little better, but I am not really happy with either system.
Has anybody seen this one? Did somebody make a caliper designed for this?