How do I know if my tires are unsafe?


From: Sgt. Troy Christianson
Minnesota State Patrol

Question: How do you determine if your tires are unsafe?

Answer: Tire talk is important anytime of the year, in winter it is important to double your efforts when maintaining your tires.

Over the years, I have investigated numerous crashes where worn tires were a contributing factor. Tires with inadequate tread depth may cause your vehicle to skid or slide out of control on a slippery or wet road surface. Although our area has seen more rain than snow this season, it is important to remember that unsafe tires can hydroplane on both wet and snowy roadways, becoming a hazard. When losing control of your vehicle, you can easily go off the road and into the ditch, or into oncoming traffic, possibly causing serious injury or death.

According to Minnesota State Statute 169.723, a tire shall be considered unsafe if it has:

(1) Any part of the ply or cord exposed

(2) Any bump, bulge or separation

(3) A tread design depth of less than 2/32 (1/16) of an inch measured in the tread groove nearest the center of the tire at three locations equally spaced around the circumference of the tire, exclusive of tie bars or for those tires with tread wear indicators

(4) Been worn to the level of the tread wear indicators in any two tread grooves at three locations

(5) A marking “not for highway use,” or “for racing purposes only,” or “unsafe for highway use”

(6) Tread or sidewall cracks, cuts or snags deep enough to expose the body cords


My best advice is to keep an eye on your tires. Taking a few seconds to walk around your vehicle before leaving for your destination can pay off, potentially keeping you from getting into a crash. Check your tire pressure often as it can be as much as 50 percent underinflated before it is visibly noticeable. Use a pressure gauge to check each tire and know what your pressure should be. Routine maintenance is good insurance. Rotate, balance and be sure that your tires are correctly aligned according to your vehicle owner’s manual.

Having a set of tires with good, legal tread depth will increase your chances of not being involved in a crash, especially when the weather and road conditions deteriorate.

You can avoid a ticket, and a crash, if you simply buckle up, drive at safe speeds, pay attention and always drive sober. Help us drive Minnesota toward zero deaths.

If you have any questions concerning traffic related laws or issues in Minnesota, send your questions to Sgt. Troy Christianson, Minnesota State Patrol, 2900 48th Street NW, Rochester, Minn., 55901-5848. You can also reach him at


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