Tapered roller bearings are best described as:

Tapered roller bearings are designed to accommodate both axial (thrust) and radial (radial) loads, making them particularly versatile in various applications. The unique design of tapered roller bearings features tapered inner and outer raceways, which provide a wedging action that allows these bearings to handle significant loads from multiple directions simultaneously.

The ability to manage both types of loads is crucial in applications where machinery experiences not just vertical forces, but also lateral forces and thrust loads. This characteristic is particularly beneficial in automotive applications, gearboxes, and any rotational machinery where both axial and radial forces are present. Thus, the description of tapered roller bearings as capable of permitting both axial and radial loads is accurate and reflects their functional design in power transmission systems.