Gearing on an E-Maxx with a 7018 and _ Motor (also picking a motor)

[Gustav]

Welcome to the forums!
The 7018 can be used in the e-maxx but it's right on it's limit's so your right,careful gearing and motor choice is needed.Coolhand has run the 7018 i think,i believe it died in the end,he'll be able to advise you.
Do you have the controller already?
I'd guess a 10L might be a good motor,or a lower kv XL motor like an 8 XL.Running more cells with a lower kv motor should bring the amp draw down,so it might be better to run more cells with a 12L or a 9XL.Running the 12L on just 12 or 14 cells and higher gearing should draw more amps due to the higher load.