When Are Your Tires Worn Out?
Are your tires worn out? What is the standard for our Colorado roads? How can you tell on your family car?
While there may be legal requirements for the Boulder area, there are safety concerns that go beyond meeting minimum replacement mandates.
2/32 is the depth of the tire tread wear indicator bars that US law has required to be molded across all tires since August 1, 1968. When tires are worn so that this bar is visible, there’s just 2/32 of an inch – 1.6 millimeters – of tread left. It’s that level of wear that’s been called into question recently.
We’re referring to the Consumer Reports call to consider replacing tires when tread reaches 4/32 of an inch, or 3.2 millimeters. And the recommendation is backed by some very compelling studies.
The issue is braking on wet surfaces in and around Eldorado Springs. Most of us think of our brakes doing most of the work, but if you don’t have enough tread on your tires, the brakes can’t do their job. When it’s wet or snowy, the tread of the tire is even more critical to stopping power.
Picture this: you’re driving over a water covered stretch of road near Eldorado Springs, CO. Your tires must be in contact with the road in order to stop. That means that the tire has to move the water away from the tire so that the tire is actually contacting the road and not floating on a thin film of water.
Floating on the surface of water is called hydroplaning. So if there’s not enough tread depth on a tire, it can’t move the water out of the way and you start to hydroplane.
In the study a section of a test track was flooded with a thin layer of water. If you laid a dime on the track, the water would be deep enough to surround the coin, but not enough to cover it.
A car and a full-sized pick-up were brought up to 70 miles per hour, or 112 kilometers an hour and then made a hard stop in the wet test area. Stopping distance and time were measured for three different tire depths:
- New tire tread depth
- 4/32 of an inch
- 2/32 of an inch
John’s Auto Care 1900 55th St. #104 Boulder, CO 80301 303.442.2932