So i've been riding 28c tires on my roadbike for some time and a friend of mine is still rocking old 23c on 13c rims(to my knowledge/ Rigida 18 from the 90s)on his roadbike. His tires a bassically toast now and as he, liking the more comfortable 28c on my bike, could get 28s from a friend for free, we were wondering if they would fit the rim. Brake and frame clearance is not a problem, but to my knowldege 13c rims, if they are, are only supposed to fit up to 25C. The question I have now is, if anybody has actually tried this setup and if it really does make alot of difference, as I think 15c rims can fit up to 33c tires. I just wanted to ask if anybody actually has got experience with this before going on a trip and noticing some long way from home that it just doesnt work.