And the base-magic number to remember: 2/32.
While most states agree with the 2/32 measurement, there are a few that do not see eye-to-eye on this allowance. Those state standards are set a little higher: 4/32.
Then, there are year/make/model requirements of 4/32 before alignment to ADAS calibration-recalibration can commence.
The National Highway Traffic Safety Administration (NHTSA) has set the national minimum tread-depth requirement at 2/32. So, we are back to 2/32, right? Wrong. States' sovereignty supersedes the NHTSA statutes — unless it is a state where tread depth numbers are not addressed, as it is within our noted five-state measurement voids.
So, how do the rules apply to my alignment and ADAS calibration-recalibration?
Good question, because here is where the discussion begins amongst shops and technicians alike.
Let us say you have an alignment to ADAS repair in your shop. The vehicle registration is out-of-state.
It is time to verify tread-depth specification on the vehicle for alignment and ADAS calibration-recalibration. The manufacturer posts the minimum tire depth for both services at 2/32.
When we perform our measurements, the readings range between 3/32 and 2/32 — within the original equipment manufacturer specs for the services. It is time to calibrate-recalibrate.
But wait a minute.
If that particular state's tread-depth requirement is 4/32, technically you can perform the sensor reset per the manufacturer numbers. Right?
Legally, the tires would be below specifications for any service as this vehicle's registration matches a state where tread-depth laws are more robust: 4/32. After all, we are the auto pros working on this vehicle and are supposed to follow the automotive industry specifications and be in-the-know when it comes to the laws that govern our repair standards. This is one.
So, what would you do if faced with this scenario?
This is where the median splits the tread-depth requirements for services: How to handle the conflicting requirements. Technicians' opinions on the subject are vocal in both directions and circumstances. What road would you take in one of these random situations:
• Deny service unless the tires were within the registered state's specs?
• Perform the calibration-recalibration (alignment to ADAS) even if the consumer declines replacement tires — and the tread depth is below specs?
• Refer to your shop's state tire- depth laws since the service is being performed within a state with a lower tread-depth benchmark?
Confused? I'd be surprised if you weren't. For the time being, a good rule of thumb is to act conservatively regarding tire-tread-depth specs for alignment to ADAS calibration-recalibration. And that includes reviewing each entity's requirement to establish the car or light truck's base.
1. Original manufacturer tread-depth specifications;
2. Federal tread-depth specifications (for states without a minimum);
3. State tread-depth specifications.
In other words: If the vehicle owner can get a traffic ticket because the tires' tread depth is below state specifications, it is best for the shop to rule on the side of caution. And if the manufacturer specifies a higher tread depth value than either the federal or state standard, again, it is best to rule on the side of caution.
There needs to be a reasonable, cut-and-dry calibration-recalibration tread-depth guidelines for techs. We want to service vehicles properly and avoid being caught up in litigation based on tread-depth standards for alignment to ADAS service requests.