volts/amps question

[speed demon]

Wow looks like I started something.

Let's say for instance on my rustler with the medusa motor running 4S then putting in a 5S but gear it down too the same speed will I have the same run time given both bats are the same mah?

I just got done doing some speed runs geared 35/76 and it's fast but want to go more but I'm out of room for more gear unless I go milling out the slot on the motor plate.

Would like to get abit more run time but have enough power to gear up for some sick speed(with a 5S) and keep my motor nice and cool.

My MM with fan now was 121 with the 5 tooth larger gear. My motor was up to 136 but without the fan for over half the run(nasty end over end over end over end crash). Thanks