Gear Pitch
Ary wrote a terrific article on gear pitch 10 years ago that everyone should read: http://austinslotcarclub.com/forums/topic/gears-pitch-mesh-a-look-into-slot-it-variable-pitch-gears/
With the diameter of Slot.it pinions fixed, the pitch varies with the number of teeth, while all Slot.it crown gears have a fixed pitch of 48; their diameter changes. For that reason, the optimum Slot.it gear mesh is achieved with an 8 tooth Slot.it pinion. 9 tooth is OK too; 10 tooth is marginal, and 11 tooth should be avoided. I do not know the pitch of NSR pinions and crowns to know how they compare to the Slot.it gears. The pitch of the NSR gears can be calculated by using the formulas in Ary’s article.
This is a separate issue than allowing Slot.it gears in the NSR cars, but if anyone does so, the pitch should be calculated to see how well disparate gears will mesh.
Russell