I can pick up a set of 27" Rigida blue label 13-19 locally. Can I safely mount a set of 27"x1-1/4" tires on it or are those rims too narrow? Based on the information from Sheldon Brown's site, the widest tire for 13mm width rim is 25mm, 1-1/4" is more like 31.75mm. What is your 2 cents on this subject?

Edit: I just checked, the actual width of the tire is 26.3mm.

I would put a micrometer on the rim and get an accurate measurement first. I use Sheldon's guidelines on tire widths, and have not exceeded them (maybe others have). 27 1/8 tires are readily available.

guidelines are simply that, guidelines. As wrk101 noted, they can exceeeded. 27-1/4" look goofy on those smaller Rigidas.