I think a Gentleman's race is one where you team a stronger rider with a weaker rider. I read somewhere that 100 years ago in france they would team a man and his wife on a tandem with the man steering (said tandem might have been one with both the steering column and the male in the stoker position.)
The article below mentions combing a young racer with a retired pro racer on a team, with a handicap based upon average age.
http://search.bikelist.org/
I don't know why Super Champion made a rim specifically for Gentleman's racing, perhaps they were just paying hommage to a bit of terminology (like Mount Ventoux) that became famous due to cycling.
- Don Gillies
San Diego, CA