So, got to thinking: are the <smaller size (11 and 13T)> VexPro CIM pinions truly “designed for a <larger size> center-to-center distance”, or are they just leveraging the fact that you can put a slightly smaller gear in with little consequence. Are you better off designing a custom gearbox around a <smaller size> center-to-center distance or the <larger size>? Do the smaller pinions put force further on the teeth (of both gears in the mesh)?
The gears truly have been modified in design from a “stock” 11T or 13T gear. Check out this thread: https://www.chiefdelphi.com/forums/showthread.php?t=152508 and this post: https://www.chiefdelphi.com/forums/showthread.php?p=1311086#post1311086 for information on how VEX designs these gears.
I mean, do you think they’re lying when they say that? I don’t really see how you could doubt “designed for a 12T center distance” without any other implication there…
Anyhow, if you look at the CAD model or drawing, it should be very clear - the gear looks different than a normal 11 or 13T pinion does, and that is because of the addendum to make it work at the larger pitch circle. Trust the manufacturer, design for 12 or 14T spacing.
Ooh, thanks for linking to that. That post basically contained the information I was looking for when I made that thread.