Originally Posted by
grumpus
Examine the pattern of the tread - if there's some directionality it will be in the form of chevrons
That is not always the case. For a counter example, check the Schwalbe Rocket Ron:
https://www.jensonusa.com/Schwalbe-R...ound-29-Tire-3
It is directional, but one would be hard-pressed to guess the proper direction by inspecting the tread pattern.