[lincpimp]

The spiral cur bearings are a good idea, they should last longer than a strait gut gear, as the teeth are in engagement more than on straight cut gears. The bearings need to ge conical like a full size car, and they need some sort of preload, like a crush sleeve. Most likely would be too big to work well in the space available.

Good luck with the straight cut gears, hopefully they will treat the bearings better than the spiral ones did!