Continental makes wonderful 27 inch tires, as does Panaracer. The Pasela is very respected by touring cyclists. A $30 tire generally has a nicer ride than the $5 tires at K-Mart. The better tires will be rated for around 95 PSI in the narrow widths, such as 1 1/8th inch, and 85 PSI or so in the 1 1/4th inch width. A rider who weighs more than 200 pounds can benefit from riding at the maximum rated PSI.