Velo Mule

Older tire sizes. Let's start with 26" x 1-3/8" These were fairly common in the 70's mostly on three speed bikes, there were some derailleur bikes that used this size too. The size is still far from dead. There are lots of good tires out there and although rim choices are not as good as other sizes, the Sun CR18 is an excellent rim that is available in different hole number and finishes. I think it might even be available with and without an eyelet. Not only is this a good replacement for existing 26" x 1-3/8" bikes, it is also suitable for 27" bikes. 1 - 3/8" or 35mm is a good all around width for a tire, which is why it became so popular in the first place for bikes that were intended to be ridden comfortably and not needing to look like you were ready for the Tour de France. 26" x 1 - 1/2" tires are available, but there are limited choices in this size.

Then there is 27" tires. These were the performance tires from the 60's to the mid 80's. There are good tires available. I see lots of advice to change wheels to 700C to gain access to better tires. As far as I am concerned there is no problem with 27" tires. If the bike came with them, stick with them.