I have a 1983 Trek 500 with I believe 27in wheels. The tires on them are Kenda and say 27 1 1/4. I have a set of 27 1 1/4 Gatorskins lying around so I thought I would swap out the Kenda tires. When putting the Gatorskins on, they are too big for the wheel! Both tires say 27 1 1/4, how could one fit and one not fit?

Is there a chance that the wheel is actually 700c? The wheel is quite thin and uses a presta valve.

Very confusing...

According to the Trek brochure below, that bike has 27" rims and came with 27" x 1" tires. Therefore 27" x 1 1/4" should also fit.

How are they too big?

Do the rims have a hook around them for using with beaded tires? On some older rims where the inside of the rim is flat, newer beaded tires won't stay on the rim if you attempt to inflate them any where near the max pressure on the sidewall.

Wow, embarrassing. I tried again and it went on no problem. I think when I did it the first time, I had a 26in wheel lying around and mistakened it or something. No idea. Sorry!