RE: spur gears anything better??
you need to do gear meshing properly, if too loose they will strip, if too tight they will bind and shear off. There needs to be a slight bit of play between the gears. once i upgraded my clutch bells to steel, they have been fine and if you purchased your rc's in the last year, its 99% steel and not aluminum. An easy way to check is see if a magnet stick to it, if so then your ok, if not, get a steel cltuch bell.