I put a Thunder Power 13.5T sensored motor in my slash and I not sure about gearing. I right now have it at 18/87 and I also have a 19,20,21,and 23 tooth pinion gears. It has a RPM transmission case so it going on a metal motor plate but I have no idea about gearing I want to be able to run it hard and on the track also if anyone has ideas for spurs. Help !
It's going to be some work testing setups for temps but here's a website to check what speeds you would get. As far as spur start with the 86t. http://scriptasylum.com/rc_speed/top_speed.html