[suicideneil]

Indeed, the hvmaxx esc is only rated for 4s lipo. You could use the motors with a sensorless esc, but the Hv7.5 is rated at 3000kv- thats 66,600 rpms on 6s lipo. Gearing down would produce more grunt, but the bearings wont like you too much; I'd just as soon opt for a larger ~2000kv motor and run it on 4-5s lipo, and gear it taller; more grunt than you can shake a stick at, without overly high temps or rpms.