Would someone give me a quick break down of the differences. I'm not sure what to choose. It's going into a light weight 4wd on road car. I plan to run 6 cells but certainly don't want to be limited to that.
I would say the 6900 if your gonna go with 2S wen you go LiPo. Even if you went with 3S, the 6900 would probably still be my choice since it seems like your after speed.
Upto a point. If you feed too many volts to a high revving motor, it will spin too fast and overheat, de-magnetizing the magnet and probably shattering it too for good measure. Dont go over about 50-60,000 rpms at the very most I think (kv rating x volts = rpms).