Bike came with 27x1 1/4" rear wheel with dia-comp brake calipers.
I have changed to a 700c wider touring style wheel with 700x35 (iirc) Michilin City commuter tires.
My dia-comp brake calipers still work on this setup, but I've got a nicer set of gran-comp calipers w/quick releases that I really want to use, but they don't fit over my new rear setup and barely fit my front setup, which is still the original 27x1 1/8" with continental ultra sport tire? It seems these brakes don't have a long enough reach? They came off a ~79 centurion semi-pro with 27" wheels, so I'm very confused why they don't work at least up front. I could probably get enough throw out of the front one to work if I enlarged the adjusting slot to put the pads lower, right now it slightly rubs tire if I use it.
Other things I've done to the bike are-
changed suntour stem shifters for suntour bar-end shifters
changed no-name crankset for Sugino Mighty 42/52
changed (blew apart) cup/cone old bottom bracket for a shimano un54 sealed cartridge unit
5spd suntour freewheel for a 7spd 11-28 shimano
suntour honor derailleurs for suntour cyclone units (WOW do these work so much better!).
turkey-lever dia-comp non-aero brake levers for a cheap ebay set of aero levers, which I don't like because the hoods are so narrow they cramp my large hands.
I assume I'll need long reach? I plan to upgrade to integrated shifter/brake levers in the future when I come across a good deal, so if I have to buy some long reach calipers I would like them to work with what I have now in addition to some shimano 'brifters' in the future.
I plan to change my front wheel/tire to a matching 700x35 city tire setup when what is on there now wears out, but I only put about 1000 miles a year commuting to work so the front will probably remain the same for a couple years.
Here's a couple pics of how the bike has transformed just for fun