Brushless gearing

[BriaN]

I’m thinking about buying either a Kinexsis brushless combo 4000 KV with a 70A esc
Or a eBay Ocday Brushless combo- 5200 KV and a 60A esc, and I want the combo to be waterproof, does anyone have any advice for waterproof combos?
Another question- if I was running the Ocday system, what gearing should I use? Maybe stock?
And if I was running the Kinexsis system, what gearing should I use?

 

[ZavAMPMT]

We have an AMP with the Kinexsis 4000KV. We still have the stock 87t spur gear. We are running 3S Lipo most of the time. The battery and ESC never seem to get too hot. The motor depends a lot on the terrain we are running it through. Racing around the yard over fresh cut, short grass we can run a 21t pinion and the motor will run 160-170 degrees. Using the same pinion in tall un-mowed grass the motor can get really hot. I am likely going to step down to an 18t pinion and it will still be plenty fast.

We put on a T-Bones rear bumper and removed the tight fitting stock motor cover. The motor definitely runs a bit cooler.

 

[BriaN]

Thanks! Others said that stock gearing is fine too