A flat tire is one hiccup that we all fear, especially as equestrians.  USRider reminds equestrians to check their tires as they can lose their footing long before they’re worn out. Testing by Consumer Reports shows that tread can give up a significant amount of grip when it’s still at the half-way point. Checking your tires on your tow vehicle and trailers should be part of your regular maintenance. Tires should be checked once a month.

When the grooves of a tire reach 2/32nds of an inch deep, they are considered bald. A new tire has grooves of about 10/32nds. Tire manufacturers have made bald tires easier to spot by placing a series of mold horizontal bars at the base of the grooves. The bars become flush with surrounding tread when wear reduces groove depth to 2/32nds.

With diminished tread comes the augmented risk for an accident. As a tire wears, there becomes a reduction of performance in rain and snow. When those summer storms hit, hydroplaning is a big risk due to standing water from a heavy downpour. If your tires have 2/32nds remaining tread depth, resistance to hydroplaning in the rain at highway speed is significantly increased.

If you’re about to leave on a long trip, a tire check is essential. Most people in general do not worry so much about their tire tread, but more about air in their tires. While this is just as important as your tread, checking the tire in its entirety is crucial, as tire issues are the #1 reason for disablements with horse trailers.

The best way to check the depth of tire tread is with a depth gauge. However, U.S. coins can be substituted for a tire-tread-depth gauge as tires wear to the critical final few 32nds of an inch remaining depth. Consumer Reports offers the following guidelines:

  • Place a penny into several tread grooves across the tire. If part of Lincoln’s head is always covered by the tread, you have more than 2/32nds tread depth remaining.
  • Place a quarter into several tread grooves across the tire. If part of Washington’s head is always covered by the tread, you have more than 4/32nds tread depth remaining.
  • Place a penny into several tread grooves across the tire. If the top of the Lincoln Memorial is always covered by the tread, you have more than 6/32nds tread depth remaining.
  • Once you have determined the approximate remaining tread depth in the first location, you can complete your measurement of each tire by placing the coin into additional locations at least 15 inches apart around the tire’s central circumferential groove, as well as in its inner and outer grooves. This will help detect uneven wear caused by mechanical or service conditions.


While inspecting your tires’ tread depth, be sure to check for dry rot and pressure as well. Trailer tires typically deteriorate due to dry rot from age before they wear out and should be replaced every 3-5 years regardless of tread wear. In addition, trailer tires are more prone to uneven wear due to under-inflation. Upon inspection of the tire, the outer edges of tread would show more wear than the center. This condition also leads to blow-outs-–the number one reason for disablements relating to horse trailers.

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