The Tost Aero 4.00-4 (P/N 064491) is a high-strength aircraft tire designed for 4-inch aviation wheels, commonly used on light aircraft, gliders, and ground support applications. It features an 8-ply reinforced carcass (8PR), giving it high load capacity and durability for repeated takeoff and landing cycles.

This tire is part of TOST’s aviation-specific tire line, built for rugged operational environments including grass strips, unpaved runways, and training airfields.

Its primary features include:
Aircraft-grade 4.00-4 tire size for aviation wheels
8-ply reinforced construction (8PR) for high load capacity
Tube-type design (requires inner tube)
Outer diameter approx. 300 mm, width ~100 mm 
Rated static load up to ~600 kg per tire 
Designed for gliders and light aircraft main or nose gear use 
Suitable for grass, gravel, and mixed-surface runways
Durable cut-resistant rubber compound for long service life

The 064491 is widely used in general aviation because it balances strength and weight while remaining compatible with standard 4-inch aircraft wheel assemblies, making it a common OEM-style replacement tire in glider and light aircraft maintenance.