I run mine on 2s geared 23/90 about 36mph in my rustler and it runs ok but has a slight cog on a slow start and from time to time cuts out for a few secconds like my MMM did before I swaped back to 1.21 firmware. So it may be in the programing. I have about 20 packs through it and after a diff rebuild and mip cvd upgrade I can say I love the motor.