I can't say that I've seen factory-sealed cranksets with mixed NR/SR rings. However, this setup was pretty popular among the Euro pros in the early 80's, as I recall. It was always an SR big ring and an NR inner. At the time I assumed it was because the NR ring was stiffer, making it good for climbs, or something like that. In hindsight this is probably off the mark since it is the big ring that is more prone to flex and the accompanying ft. der rub. More recently it has come to my attention that Campy made 41t NR inners, but made few or no 41t SR inners. So, my current theory is that back in the day, guys who wanted the smallest ring that would fit on the 144mm cranks, had to go with the NR inner.
BTW, there seemed to be a fair amount of NR usage into the SR era. Not only the inner rings and the obvious NR BB's and SL pedals, but the old, reliable NR posts seemed to get use too. It stands to reason, since SR posts can slip. Also it is not as easy to maintain a saddle angle when switching out saddles on an SR.
> I believe this came up once before.
\r?\n> I recall reports that cranks came through with one
\r?\n> Super Record ring and one
\r?\n> Nuovo Record ring.
\r?\n> If anyone has seen a few of these, was there a
\r?\n> pattern? (i.e.; the small ring
\r?\n> was always NR, or the large ring was always NR)
\r?\n> I have two Nuovo Record rings on a half step setup
\r?\n> and it looks kind of
\r?\n> clunky so it made me wonder.
\r?\n> Pete Geurds (nothing better to think of at 0550!!)
\r?\n> Douglassville, PA