MM/Feigao cogging

[BrianG]

The "magnet" is actually just a ferrite material used to supress RF noise from confusing the receiver and/or the ESC. I suspect the cogging people are noticing is from less than ideal load (gearing, weight) on a given motor. The 7XL can pull a substantial amount of current especially on heavy acceleration so any efforts to reduce the load (and therefore current draw) on it somewhat through gearing, reducing weight, and using smaller tires will help a lot, as you've noticed.

My Hyper 8 buggy is kinda heavy at something between 10-12 lbs, geared with a 14T pinion on a 2600 KV Neu motor and I never have cogging with the Quark 125. Personally, if you're in a hurry, I'd get an MGM or Quark to get your setup running right. However, if you can wait, the MMM sounds like it might be a better and cheaper choice - that is if it ever comes out.