Originally Posted by John E

I have owned two early 1970s UO-8s and a 1980 PKN-10 (successor to the PR-10), and have ridden them extensively. The PR-10 will give you about a 2-lb. weight advantage over the UO-8, in addition to a livelier, more resilient ride. It also has an integral derailleur hanger, which you can easily adapt to accommodate a SunTour or Campagnolo derailleur if you do not care for Simplex. I give it a solid nod over the UO-8.