There is no correct answer tread wear rating's can only be compared within the tire manufacturer itself aka a michelin to a michelin or a goodyear to a goodyear. You can not compare a michelin to goodyear or yokohama
It is an indicator of tire tread wear.
Yes, because the tire gets hot and this causes the tread to wear faster.
Tread wear indicator
It really does not matter how many there are as there are several around the tire. When the tread wear indicators appear flush with the tread you have 1/16" tread left and should look to replace the tires very soon.
When the tire tread wears down to the wear bars, the tires are ready for replacement.
Completer wear of tread surface -(creating an unsafe tire ! )
It is the rubber marker within the tread to show tread depth. It is also known as a tread wear indicator
In the middle of the tread area,
Tread wear indicator
A flat tire can lead to reduced tread wear and sometimes blowouts.
The three important tire checks to make are proper inflation(pressure), adequate tread(tread depth), and normal wear(wear and tear).
The minimum tread depth in New York is 2/32". U.S.- and European-manufactured tires have wear bars or tread wear indicators molded into the tread. There are portions of the tire that are raised 2/32". When the tread wears down so the tires are no longer legal, these portions will form a smooth bar across the tire in several places.