Military Tire Inflation Systems
Military vehicles such as AFVs (armored fighting vehicles), trucks and utility vehicles may have central tire inflation systems (CTIS) that allow operators to adjust the pressure in each tire. This capability allows adjustment of the tires to suit the current terrain conditions, and can improve fuel consumption and aid in freeing stuck vehicles. The system may have selectable modes for different conditions, and will work to maintain optimal pressure at all times.
Lowering the pressure increases the surface area of the tire that is in contact with the ground, making it easier for the vehicle to traverse soft or loosely packed terrain such as mud, snow and sand. It also reduces wear and damage to the tire. Higher tire pressures are suitable for more solid terrain and for higher speed travel.
Military CTIS may also attempt to maintain tire pressure in the event of a leak or puncture, or even after the tire has been damaged by multiple bullet holes.
Runflat Tire System
Military runflat tires are also designed to allow continued operation following damage to the tire, allowing the vehicle to carry on with the mission or withdraw from conflict. This may be achieved using a number of technologies.
Self-supporting runflat tires use reinforced sidewalls that are able to withstand being crushed between the tire rim and the ground even with loss of pressure, allowing the tire to stay on the rim.
Auxiliary-supported runflat tires use a ring insert that can support the weight of the vehicle after pressure loss, and are the most common solution for military vehicles, often allowing the vehicle to continue to operate for up to 100 km. The inserts are typically made from rubber, composites or other flexible shock-absorbing materials.