My friend gave me his old sanwa road bike that had been sitting in the snow for about a month. It looks like the one from the 1979 movie "breaking away" but with a different color and brand (to give you an idea of how old it is). Anyways, the brake pads look brand new, they look like they engage properly when I use them, they stop the tires instantly when I use them while I have my bike flipped upside down, but then when I hopped on my bike and pedaled to about 10 mph and pulled the brake levers, I could hear the brakes quietly squeaking a bit against the metal rim of the wheels, but it took 50 feet and a crash into a 10 foot tall pile of snow in an empty parking lot across from my apartment to stop... They felt like they had been cut as soon as I hop on the bike but work fine when I'm off it. From what I can tell, they are supposed to be positioned so they hit the metal wheel rim (they are), in a "V" shape pointing forward (they are), and from what I can tell they just barely don't touch the rim while I'm not pulling the levers. Any ideas on how I can fix this? Any and all help would be appreciated! Thank you.
It is quite possible the brake rubber is old. Or the rims may have an oily residue on them. As the pads age they become hard and dry. The result is long stopping distances and brake fade. You can try to use a file on the pad brake surface to remove the driest rubber. Avoid sandpaper as the grit can get lodged in the rubber and damage the rim. The results don't typically last for long. Replacement pads are inexpensive and easy to install.