Are Zippy Lipos safe with a Castle MMM Speedy?

[fastbaja5b]

So based on what is being said here, one should be fine to run it on 6s with the 20t pinion and if anything it should be easier on the system than running on the 25t pinion

so why are we being told that to run on 6s we must run the 25t pinion as is the feedback here:
http://www.ausrc.com/forum/showthread.php?t=15868

Where the blame has clearly been laid on the user running the 20t pinion and not the 25

If anything, if you're going to change gearing shouldn't it be down to like a 15/16t pinion?

And I still haven't had a reply from castle support, been what, 3-4 days now? :( not cool!