トレッドウェアインジケーター

noun

tread wear indicator

A raised bar or mark inside a tire's tread grooves that becomes visible when the tread is worn down, indicating the tire should be replaced.

• タイヤのトレッドウェアインジケーターが出でてきたら交こう換かん時じ期きです。

  When the tread wear indicator appears on your tire, it's time to replace it.