During winter trials of the amphibious tank it was established that mobility and agility of the tank depends on the depth and condition of the snow. Snow that affected the tank's mobility was grouped into the following categories:
- Fresh, loose, dry snow.
- Packed dense snow.
- Packed wet melting snow.
The tank's clearance is 260 mm, and so if the tank is driving in snow more than 400-450 mm deep the weight of the tank compresses the snow underneath depending on the condition of the snow.
- If the snow is dry and loose, the tank can drive in snow up to 800 mm deep, a part of the snow is thrown side to side. Some of the snow is compressed to the degree that the tank's tracks don't lose their grip. Resistance to movement is increased drastically, only driving in 1st and 2nd gears is possible.
- If the snow is packed and dense, it is possible to drive as long as it is less than 500 mm deep. At greater depth movement is impossible because the tank bottoms out. The tank cannot compress the snow with its weight so that the tracks reach the ground and could grip it. In this case the tracks are suspended and begin to slip.It is impossible to proceed unless the snow under the tank is dug out. One person using a regular sapper's spade can free the tank in 30-40 minutes.
- If the snow is packed and melting, the tank can drive as long as the depth is less than 300-350 mm. At a depth of 350 mm the tank bottoms out and the tracks slip.
When driving on country roads and snow-covered highways the tank's narrow wheel base makes one track run on snow and the other on the snow compressed by vehicles that passed earlier, as a result of which one track propels the tank faster than the other and has to be constantly braked, which wears out the brakes.
It's very hard to drive the tank along a cleared path. It bottoms out and the tracks start to slip. It is very hard to dig out compressed snow from under the tank.
It is very easy to drive the tank on a good road. It shakes very little, the engine does not overheat, it is easy to control.
The tank's main drawback in winter is that its clearance is small, which means it can't drive in deep snow.
- Highway: 195 km
- Country road: 158 km
- Off-road: 16.5 km
- Total: 369.5 km
Proving grounds chief Shatagin
Chief of the trials department Morozov
Chief of station #1 Strogonov"