We have made a new mould just to give to our customers the posibility to choice more in a pinions range. This is a set of 7t, 8t, 9t and 10t and they have a special design in the axis hole, and we can asure that the pinion will not come out. We think that we have solved the problem of temperature dilatation of plastic pinions with this new design, the preasure over motor axle is heavy and its really dificult to loose a pinion.