At a first glance it would seem that the two categories refer to the same thing. There are a number of major differences between the mounting tents and the expedition tents.
Mountain tents models can be used, like their names suggest, on the mountains. However, there are models of 3 or 4 seasons, while the expedition ones are only for 4 seasons. The differences don’t stop here.
3 seasons mountain tent
Mountain tent for 3 seasons (spring, summer, autumn) cannot be used in the winter, because they do not resist in case of snow storms. Snow can get inside, due to the lack of a sleeve, which stops air circulation underneath the outer foil. These models have 3 poles, which intersect in a single point where the highest point on top of the base is. The impermeability of the outer foil it`s at least 4.000 and the floor foil is at least 5.000. These are lighter than the 4 seasons and the expedition model.In general, it`s used polyesterwrapped with polyurethane.
4 seasons mountain tent
This tent can be used anytime during the year. It is designed for a better resistance to the wind and snowstorm. From the construction point of view, the difference between these model and 3 seasons refers to the number of intersections of the poles (the number of knots). These have, in general, 3 knots. It is called semi-Geodesic tents. The impermeability of the outer foil it`s at least 5.000, and floor foil it`s at least 7.000.
Whether if they are 3 or 4 seasons, in general, mountain models have a waterproof shell (the coating of outer and floor foil) of polyurethane (PU). The exterior foil is made of polyester. In case of nylon use, it is indicated to have a silicon coating. The poles are made of Duralumin and can have a 8.5 mm thick or can be thicker.
Examples in this category: Backside T-9
Expedition tents are used in high alpine areas (4000 m) or in Arctic areas. All of these models are for 4 seasons. Their design stops the snows to enter inside. These tents are not found in camping sites because are intended for those who venture into real mountain expeditions.
The outer foil is made of nylon (polyamide) with silicon coating. These models have a minimum 5 poles and at least 5 knots and the poles are made of Duralumin with at least 9.5 mm thick. This silicon coating resist very well in time against ultraviolet radiation, protecting the occupiers.
The most recommended colors are the bright ones: orange, red or yellow, that make it highly visible in a landscape dominated by white or gray. Low height and aerodynamic shape gives extremely high resistance during snow storms. These models have to withstand harsh conditions and sometimes for a few days. The ground fixing is done with the help of a large number of nails. These models are called geodesics. The impermeability of the outer foil it`s at least 5,000 and 10,000 for the floor.
Example in this category: Easton Mountain Products Expedition