Hey everybody, my rear tire has developed a bulge in it so I need to replace it. When I bought the bike (used) it came with 27 x 1 1/4 tires. I'd like to get some thinner tires does anybody know what sizes would work for this. I checked Sheldon Brown's site (https://sheldonbrown.com/tire-sizing.html) but his chart showing safe size combinations doesn't have anything above 25.

Can any of you give me some insights?

its the ISO you after 630.

I use 27 x 1 1/8 on most of my bikes with 27" wheels. They also make 27 x 1 but I find them too narrow and also difficult to install. Panaracer Pasela is a good tire and can be ordered on-line for under $20 per tire.

hmm, I was hoping to go smaller than 27 but I'm not willing to buy a new set of wheels. Oh well I guess.