Mountain biking is a growing activity in Ecuador especially in the highlands. There are also clubs and tournaments throughout the country. Although there are not any dedicated courses, the network of minor roads on the slopes of the Andes make ideal routes to explore by mountain bike. Unless you are on a tour or bring your own bike you will be limited by where you can hire a bike from. There are companies or shops in quite a few highland towns which hire mountain bikes for half a day or a day. The most popular place to ride is Baños, where most people choose to cycle down towards Puyo, either to the waterfalls (all downhill) or all the way to Puyo (mostly downhill) and then put the bike on the roof of a bus to come back.
Another option is to go on a mountain biking excursion. These usually last one day. Cycling down a volcano is especially popular. The excursion involves cycling downhill a fairly straightforward and exhilarating route, either with a guide on a bike and/or a mechanic monitoring you from a support vehicle.
Some agencies also organise multi-day trips which you can also combine with other activities. Here is a list of destinations that might appeal to you.
Chimborazo downhill (from Riobamba)
Cotopaxi downhill (from Quito)
Quito - Otavalo
Otavalo – exploring lakes in the area
Cajas National Park (from Cuenca)
Lloa – Mindo
Tours should be led by a guide and accompanied by a driver / mechanic in a 4x4.
The following tour operators have been recommended to me:
Aries Bike Company