Tires: Tire Safety & Replacement Quantity

What it Does

Tire traction grips the road, and tread depth gives room to expel water out from beneath the tire to prevent hydroplaning.

Why This Matters

Loss of grip with the road reduces or eliminates control of the vehicle and can lead to a crash. Hydroplaning is a dangerous condition in which so much water gets between the tire and the road that the tire cannot maintain good contact and grip with the road. This greatly reduces or eliminates the ability to stop and steer the vehicle.

Possible Problems and Concerns

Tires become progressively less safe as they wear. Brand new tires have a lot of tread depth available to expel water out from under the tire. A brand new tire may have anywhere from 8/32″ to 11/32″ of tread depth. As the tire wears, that tread depth gradually decreases, leaving less and less room for water expulsion.

Technically, a tire with 8/32″ of tread depth has less room for water expulsion than a tire with 9/32″ of tread depth. But in either case, hydroplaning or severe traction loss are rare enough that folks don’t want to replace a tire with that much tread on it.

Once you get down to around 5/32″ of tread depth, the risk of losing significant traction in wet weather can go up substantially. This affects your ability to properly (and quickly if need be) stop and steer the car. Some tires and vehicle combinations will perform better under such conditions than others. Suspension design, tire quality, and tread profile are all relevant here. Minimum legal tread depth is 2/32.” As that tire wears down even further (4/32″, 3/32″ etc.) the risk of losing traction (and the risk of hydroplaning) goes up even further, but this doesn’t mean that the tire has worn bald yet or even reached the minimal legal tread depth.
This leaves the question of how much money you want to spend in pursuing safety. We’re not going to advocate replacing all four tires every year. And we’re not going to push you to replace tires at 6/32″ of tread depth. We won’t push you at 4/32″ or 5/32″ either, but we may bring up the concern or ask if you’ve started to experience some traction loss.

So, let’s say your vehicle has one bald tire. How many tires get replaced? If it has one bald tire and 3 almost new tires, we’d suggest only installing one tire as long as it’s an exact match for its neighbor on the other side. But if your car has one bald tire and another tire that’s worn to 3/32″ or 4/32,” you may find replacement of at least two tires to be a more cost effective option that benefits your safety.

Recommended Parts Brands

  • Bridgestone
  • Firestone
  • Hankook
  • Michelin
  • Pirelli
  • General (Altimax)