The nc24 has 15T-45T, so a ratio of 3
The nc30 has a 40T rear
So a set up of 13T-40T would give a ratio of 3.08

a set up of 14T-42T would also give a ratio of 3

Timon wrote:

Neosophist wrote:(it'll acellerate fast with a 40T NC30 sprocket though!)

Other way around isn't it?

putting a 40T on a nc24 you'd lose acceleration

Yes, I was thinking of front sprocket.

While that is the actualy sprocket ratio you'd want to look at internal gearing differences to determine rpm etc and what will be best.

I'll dig the information out soon