Starting in 1987 The Dave Scott Ironman was offered in two models the Expert and the Master. The Master retained the Shimano 600 Componentry and the Expert was the cheaper version of the Ironman, and it featured the new Shimano 105 components which was a redesigned grouppo from its predecessor 105 "Golden Arrow". 105 Brakes with SLR was favored at that time over the more expensive 600 since it featured the Shimano SLR system, 600 would get SLR a year later in 1988
It is unclear but in 1989 Centurion dropped the use of Shimano 105 and the expert was outfitted with Suntour GPX componentry. As with the rest of the centurion line 1989 would be the last year.
The sloped fork crown of the Master was replaced by a unicrown fork. the Copper Arayas were replaced with the Wolber Super Champion Alpines until 1987 and ultimately becoming the Araya CTL 370 in 1988 and 1989. The expert continued the famous ironman color of red/white, and for 1987 only it also came in the famous/infamous Magenta/Yellow "Miami Vice" theme.
1988 Brought on a couple changes but mainly was the Paint schemes that changed. The paint scheme has changed from contrasting head/Seat tubes to a fade paint job that the outside colors are the secondary and the primary color is in the middle.
The final year of the expert, in 1989 it received a grouppo change, Suntour's new grouppo GPX was introduced and was utilized on the 1989 Expert. also in this year they utilized a solid color for the first time on the Ironman's with the expert being a Solid Black color scheme.
1987 Ironman Expert Magenta/Yellow (source: fleslider)
1988 Expert Bright Marine Green/White (source unknown)
1988 Expert, Red/White (source Craigslist)
The Experts were "straight" fades, with one color blending into another
1989 Ironman Expert Black (source: fleslider)
1989 Ironman Expert Blue Smoke/White (source: unknown)
* Index Mode:23T Max, Friction Mode: 26T Max (max difference 13T), total capacity 26t