7XL 9920 gearing???
 

ok bro have a lightweight maxx with revo tires& rims.. looking for gearing help with the above set-up.. also running 4s li-po.. thanx for the time.. not running strobe so will be 66-72 on spur gear. Not looking to break speed records just good speed and runtime.. thanx
phil

20t pinion is nice to run at.

is 7xl too hot of a motor? just trying to get some things figured out.
phil

7xl on 4s should be fine. I would start about stock gearing. Not sure if you
have the stock diffs or not. 18 66 is a good starting point.

what type of speed am I looking at for stock gearing?yeah stock diffs.
phil

I would say about the 35 mph. Just a random experenced guess.

How tall are the revo tires?
This will help with speed calculations: http://www.scriptasylum.com/rc_speed.html

I would go 18/66, if it runs hot, than go to 16. I ran 16 and it worked great.