The wear of the center: tires overpressure
    If the tire pressure is too high, the center of the tread will bear most of the weight, which leads to faster wire of the center than the outside edges. Uneven tire wear will shorten tire’s life. Give a routine check on the tire pressure. Tires that are not adjusted correctly or have mechanical problems can lead to abnormal tire wear, too.
    Cup-like, or pit-like wear in the tread: Partial wear
    Cup-like wear (also known as pit-like wear or grooves worn) is most common in the front tire, but it may also occur in the rear tire. This may indicate the tire is uneven or there is excessive wear of parts in the suspension or steering system.
    Jagged edges: no adjustment
    The jagged or feather-like edges in the tread are scraped by the unsmooth ground. 
    To solve this, inclination angle or camber angle should be adjusted. The proper tread depth is critical to normal tire performance. If traction in slippery roads reduces or changes, it indicates the depth of the tread pattern is not sufficient. Once the tread depth reaches 0.16 cm, the tire must be replaced.