I use the same ESC in my Heavyweight so I would disagree that it's not suitable for a middleweight.

Your probably not even 60 kg compared to my 110 so it must be something else.

I would look at the ratio first, if it's on the drive or weapon side.

Also driving robots is a bit like driving a car, if you put your boot to the floor and

try pushing others around excessively-somethings going to break.

I use these ESC's because they are affordable and the next step up are scary prices

especially if your just in it for fun rather than a must win frame of mind.