Yes, Nitrogen is better than air, IF you have it readily available, use it. http://www.popularmechanics.com/cars...stions/4302788
The 50 psi max (3.45 bar) is from the tire manufacturer for the Blizzak DM-V1, the only one of the Blizzak available in the US that I could find. That is NOT a recommended pressure, just a maximum. The TPMS would be set off to tell you of low tire pressure at about 28 psi (1.93 bar). You can vary the pressure for ride comfort but if you get to low you'll also run into side wall under-inflation and it could affect the cornering significantly.
Bridgestone's description of this tire:
The Blizzak DM-V1 is Bridgestone''s Light Truck/SUV Studless Ice & Snow winter tire developed for the drivers of pickup, crossover and sport utility vehicles looking to combine grip in snow and on ice with reassuring handling on wet roads and in slush. The Blizzak DM-V1 is designed with a focus on ice traction and braking, as well as wet road handling and hydroplaning resistance to provide wintertime driving competence.
The Blizzak DM-V1 uses Bridgestone''s Multicell Z compound featuring microscopic bubbles and tubes to absorb the thin film of water that forms as tires run over packed snow and ice, while micro bite particles contribute to the edge effect that improves grip on packed snow and icy surfaces. Other compound improvements include the addition of a special polymer that improves silica dispersion to increase wet grip in chilly temperatures by suppressing the influence temperatures have on rubber hardness.
The Blizzak DM-V1 directional tread pattern features low void to increase contact area on the road. Groove distribution has been optimized with four straight grooves to assure efficient water evacuation while two center grooves criss-cross to improve drainage and offer strong edge effect at all angles, giving higher snow and wet performance with better grip in all directions. The Blizzak DM-V1 also incorporates advanced 3D Wash Board Z Sipe technology that increases both block stiffness for handling in the dry and increases the biting edge effect on frozen surfaces.
The Blizzak DM-V1 radial meets the industry''s severe snow service requirements and is branded with the mountain/snowflake symbol.
NOTE: The first 55% of the Blizzak DM-V1 tread depth features the Multicell Z Compound while the remaining 45% features a standard winter tire compound. When the Blizzak DM-V1 is approximately 50 percent worn, a depth indicator molded into the tread design lets the driver know that the remaining tread is reaching the end of its ability to provide beneficial snow traction.