[Si Coe]

Within reason.

Specs are vaguely useful within a range to let you identify the current wind for you, and specifically what the jump is between winds. For example for many brands 7.5t-5.5t covers between about 4500kV and 6000kV (not a huge change) and then 4.5t is suddenly 7500kV, which shows why we don't use them.

But there is some validity to using them to compare motors from different ranges too, if you assume they are based on equal technology. In theory if two manufactures sell 5.5t motors, one at 5500kV, the other 6500kV if would be fair to assume the lower kV one offered more torque. However it is possible the 6500kV features better magnets etc and actually offers the same torque (its just an all round better motor) .