Cable Routing
 

I have an older Raleigh which was originally designed for centerpull brakes, but was later fitted with sidepulls. It has the mounts on the side of the frame for the centerpulls still, where the cable housing stops, bare cable runs for the length of the top tube, then the cable housing starts again. Would routing the cable through this mount work with sidepulls? Thanks.

yes

Yes, there's absolutely no reason side pulls would be any different. The only (minor) issue might be if the guides are below the top tube the wrong, but you can still route it across.

Figured it would be fine. Thanks guys.

Alternatively....you could streamline the cable housing if you ran continuous housing and used 3 cable clamps instead of the braze-on mounts. The wire would be better protected from corrosion in full housing and the routing to the rear caliper would be cleaner, coming from a higher point and dropping down along the saddle on the guaranteed 'correct' side.