I picked up a 24" Schwinn Speedster from a local guy via Craigslist for 50 bucks. I'm trying to fix it up for my girlfriend. It was in great shape, so I don't have to do much to it.

The problem is the wheels/tires. The original tires were cracked, and completely shot.

Best I can tell, the rims are Schwinn S7 rims, which means they should hold 24 x 1-3/4 tires, which is what the original ones said on the side of them. The original tires have since been disposed of, so I do not have them to measure.

I already learned my lesson about 24 x 1-3/4 vs 24 x 1.75 and how they are completely different, but I've tried both, and I just can't get the 24 x 1-3/4 tires to fit onto the rim. I can't even get the first side of the tire onto the rim so I can put the tube in and the rest of the tire. I can get it about 2/3 - 3/4 of the way on, but it seems like I need another inch or so.

Is there a trick to this tire size? Am I completely wrong in the size, even though that's what the originals said on them? Should I take the tires/wheels to an LBS and have them install them for me?

I'm at a loss. HELP!!!