Think the manufacturers should rethink the whole variable speed idea on their mowers. The new systems that the likes of Hayter, Viking (Stihl), Cobra, and many others are now using is a complete mare. A load of unnecessary moving components that ware out even when a majority of people only use it in one speed.
In my opinion for reliability they should supply a speed kit. A larger or smaller front pully with matching belt. Once fitted will be a much more reliable system.