What are the standards for tire tread in the 2021 vehicle inspection regulations?

[Cinna]

The 2021 vehicle inspection regulations for tire tread require the use of a tire tread depth gauge. If the tires are severely worn and the depth does not meet the standards, the vehicle will not pass the annual inspection. Below are the relevant details: 1. New axle length inspection: The main purpose of this new inspection is to strictly monitor illegal modifications such as extended axles. Vehicles undergo safety inspections before leaving the factory, and unauthorized modifications by owners may compromise vehicle safety. 2. New vehicle lifting device inspection: The lifting device inspection primarily examines areas such as the engine hood, trunk lid, and window lift mechanisms to assess vehicle safety.

[LeBrody]

I just helped my younger brother with his car inspection a few days ago and specifically researched the new tire regulations. Currently, the inspection mainly checks that the tread depth of your tires must not be less than 1.6 mm. You can insert a coin into the tread groove—if you can see the national emblem pattern on the edge of the coin, it’s time to replace the tire. It’s not just about the depth; the tread patterns on both sides of the tire must be consistent. Especially for tires on the same axle, you can’t have one with horizontal treads and the other with vertical treads, as this can easily cause skidding in rainy conditions. Once, I saw someone with a modified car using a second-hand slick tire, and it was immediately rejected by the inspector. Deep cracks are also a problem—if they exceed 6 mm, the tire is directly disqualified. It’s best to prepare a tread depth gauge in advance and measure it yourself, so you don’t waste time waiting in line for the inspection only to be rejected.

[HazelFitz]

Last time while queuing for the annual vehicle inspection at the DMV, I overheard some car owners discussing tire regulations. The new rule emphasizes that tread depth must exceed the 1.6mm threshold, with inspectors using a caliper with a graduated probe to measure inside the tread grooves. Both tires on the same axle must have identical tread patterns - mismatched left/right treads aren't allowed. Someone tried cutting corners by replacing just one tire, only to get flagged for tread pattern inconsistency with the old tire. I've even seen modified cars using semi-slick tires on front wheels being ordered to revert to standard tires on the spot. Note that sidewall bulges or cracks over 6mm mean instant failure - driving such tires in rain is gambling with your life. Recommendation: photograph new tires during replacement as proof of tread consistency for future inspections.

[LaMadeline]

After the implementation of the new regulations, tire failures account for over 30% of annual inspection rejections. There are three mandatory requirements: all tire tread depths must be ≥1.6mm, measured with a specialized depth gauge; tires on the same axle must be of the same brand and tread pattern; retreaded tires are prohibited. Once, an SUV was rejected because its left front tire was replaced with a different brand, even though the tread depth was sufficient. Steering tires face stricter requirements—uneven wear is unacceptable. If the tire sidewall shows visible cord layers or cracks exceed limits, it will be directly deemed unserviceable. It's recommended to place tape at the 1.6mm mark from the tire wear indicator for easier self-inspection.