Most US states require a minimum of 2/32 of an inch (approximately 1.6 mm) of tread. If you intend to drive on wet roads 4 mm may be the minimum tread depth needed to stop and steer effectively. Without at least this much tread the tire cannot move water away from the tread fast enough to maintain adequate traction. To drive with less tread is not illegal until you reach the legislated minimums, but it may not be safe.
In most parts of the USA it is 2/32 of an inch.
Minimum tread depth for all 4 tires is 2/32"
in Illinois it is 4/32 front tires and 2/32 all tires
It depends on the legislation of the country in question
It's not allowed. It is a violation of vehicle safety regulations. If you'd get caught out in rain they'd hydroplane real easily, that's why the law require a certain minimum tread depth.
Probably. However, it's best to stick with what the vehicle manufacture calls for on the door decal (driver's or passenger's door jamb).
All tires on vehicles driven in Missouri must be safe. There is no listed minimum tiretread depth or mention of tire grooving in the laws.
In the United States, the tread has to be 4/32 (3.17mm) or more on the front tires and 2/32 (1.58mm) or more on the back tires. rear tires can be retreaded but not the front "steer" tires.
2/32 of an inch in most parts of the USA. Local laws may vary.
4/32 on steer axle.2/32 on all others
In Oregon there is no minimum thread depth, but just that Oregon requires that tires be in safe operating condition, without any bulges or exposed cords.
On or before your country's legal minimum requirement for tread. If in doubt see out a qualified fitter to check the tread depth for you