I found a Tri-A frame for a friend in Chicago. It was a beautiful blue and white. From what I can tell in the 1987 catalogue, the Tri-A was the top production Nishiki bicycle that was made out of steel. Nishiki also had a lugged carbon frame which was supposed to be a step above the Tri-A (but we all know that's ridiculous). The Tri-A however, is not the highest end Nishiki ever made. Given that it is Tange 1 however, you can assume that it's pretty darn good. Having never owned an Ironman, I can only speculate on geometry but I think they are about the same, since Nishiki and Centurion seemed like they were sister companies.