Checking Tire Quality

Good Tread Does Not Mean a Safe Tire

Tech Tip of the Week | Encks Auto Repair By Paul Enck | Call: 727-822-1

The Problem Most Drivers Miss

A tire can look perfectly fine on the surface and still be on the verge of failure. Paul Enck from Encks Auto Repair has a real example in the shop this week — a motor home headed on a long trip with tires that would never make it.

“The tread on this tire is excellent. The tire has lots of tread, it looks very well — but if you get out here on the outside, you’ll see that the tire is cracked. I can even stick my screwdriver in parts of it, which means it’s about to fail.”

— Paul Enck, Encks Auto Repair

Why This Is So Dangerous

The tread is not the only thing that keeps a tire intact. The sidewall holds the entire structure together. When it cracks deeply enough that a screwdriver can penetrate it, the casing is compromised and a blowout is not a matter of if — it is a matter of when.

Heat and cold accelerate the process. On a long trip, tires heat up and cool down repeatedly. Every cycle puts additional stress on already weakened rubber.

“These tires will never make it to the east coast. Once it heats up and cools down, it’s going to start losing casings.”

— Paul Enck, Encks Auto Repair

What to Look For

Do not just glance at the tread. Get down and inspect the full tire including the outer and inner sidewalls.

• Surface cracking — small cracks across the sidewall are an early warning sign
• Deep cracking — cracks you can press into or insert an object into mean the tire is already failing
• Inner sidewall damage — the inside edge of the tire is easy to miss but just as critical to check

Who Needs to Pay Extra Attention

This is especially important for:

• Motor homes and RVs — often stored for long periods which accelerates sidewall deterioration
• Trailers and towed vehicles — tires that sit unused are prone to cracking even with low mileage
• Any vehicle going on a long trip — heat cycles during extended driving push compromised tires over the edge

Pro Tip: Always inspect your tires fully before any long trip — not just the tread depth, but the entire sidewall on both the outside and inside edges. A tire that looks road-ready from the driver’s seat can be dangerously close to failure up close.

Frequently Asked Questions

1. Can a tire with good tread still be unsafe?

Absolutely. Tread depth only tells you how much rubber is left on the surface. Sidewall cracking is a completely separate issue that has nothing to do with how much tread remains. A tire can have plenty of tread and still be structurally compromised.

2. What causes sidewall cracking?

Age, UV exposure, ozone, and prolonged periods of sitting without use are the main causes. Rubber loses its flexibility over time and begins to crack even if the tire has not been driven many miles.

3. How deep does a crack need to be before a tire should be replaced?

Any crack deep enough to insert an object into — like a screwdriver or fingernail — means the tire needs to be replaced immediately. Surface-level hairline cracking warrants a professional inspection to determine how serious it is.

4. Are RV and motor home tires more prone to this problem?

Yes. RVs and motor homes often sit unused for months at a time. Tires that are stationary for extended periods develop cracking faster than tires that are driven regularly. Age matters more than mileage on these vehicles.

5. Can cracked tires be repaired?

No. Sidewall cracking cannot be patched or treated. Once the structure of the sidewall is compromised, the only safe option is replacement.

6. How do I check the inside sidewall of my tire?

Turn the wheel all the way to one side to expose the inner sidewall and crouch down to inspect it. Alternatively, have your shop inspect the inner sidewalls during a tire rotation when the wheels are already off the vehicle.

7. How often should I inspect my tires for cracking?

At every service visit at minimum. Before any long trip is equally important. If your vehicle sits unused for weeks or months at a time, inspect the tires before putting it back on the road.

8. Does tire age matter even if the tread looks fine?

Yes. Most tire manufacturers recommend replacement after six years regardless of tread depth or visual appearance. The DOT code on the sidewall tells you the week and year the tire was manufactured.

9. Is this more of a risk in hot climates?

Heat accelerates rubber degradation, so yes — drivers in hot climates tend to see sidewall cracking develop faster. However, UV exposure and ozone affect tires in any climate, so this is not exclusively a hot weather issue.

10. What is the risk of driving on a cracked tire on a long trip?

As Paul’s example shows, heat cycles during a long drive put repeated stress on already weakened rubber. A casing failure at highway speed can cause a sudden blowout with very little warning — especially dangerous on a large vehicle like a motor home.