Piston Slap: Safe Thinking on Dry-Rotted Tires?

Sajeev Mehta
by Sajeev Mehta
piston slap safe thinking on dry rotted tires

Jimmy writes:


For years I traded in my Hondas and Toyotas within 18 months of purchase. However, I did not care for the newest Highlander, Pilot, and Camry, so I kept the old ones hoping the next versions would be more acceptable. While I have not had a single problem with these vehicles, with the exceptions of a few light bulbs, I’ve noticed Michelin Green X and the Continental ContiProContact have small cracks in the tread grooves. The tires have 40,000 and 55,000 miles on them with lots of tread left. I have asked tire stores and some say don’t worry while others say they are dangerous.

What is the rule for tire replacements when it comes to cracks in the tread grooves?

Sajeev answers:

A timely query: my once-new 2011 Ford Ranger is old enough for new rubber. I noticed those cracks, even with decent tread and “good” rubber between them and the wear bars. And, just like you, I certainly ain’t trading it in for a new Ranger anytime soon!

This indicates dry rotted tires, which means harder, slippery and unsafe rubber in wet/aggressive driving conditions. As the cracks grow, blow outs and tread separation failures are likely. Given the mileage, I assume your tires are also five-ish years old. Tire manufacturers have a hard stop on replacement after 10 years, while car makers (fearing Firestone-esque lawsuits?) recommend six-year replacement intervals. For a daily driven and/or primary vehicle, I’d lean closer to the six-year interval for safety concerns.

Depending on the climate (heat is the concern) and UV exposure (garaged?), I reckon we both need new tires soon. The top picture is the factory ContiTrac on my rig. The dry rot is closer to hairline cracks, not replicas of Grand Canyons. Given their admirable performance during Houston’s recent floods, these tires have several more months of life, but I’m rollin’ on borrowed time.

But looking at them up close?

Those are bigger than I remember from my last “wait for the oil to drain out” tire inspection. While I don’t see myself on a looong highway trip in the future, this is a cause for concern.

So will Sanjeev treat himself to 10 mm wider rubber so contact patch isn’t stretched so tightly and the speedo might read accurately? The autoblogosphere is dying to know!

[Images: © 2016 Sajeev Mehta/The Truth About Cars]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

Also, if your tires suck and you’re shopping for new tires, help support TTAC’s work by doing your research at TireReviewsandMore.com. — TTAC staff.

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8 of 71 comments
  • Rpn453 Rpn453 on Jun 28, 2016

    Those surface cracks wouldn't bother me. I've seen far worse. But I have a relatively high tolerance for risk. New tires certainly would be safer, allowing a much greater safety factor in an adverse situation such as an under-inflated tire at high speed. They'll also likely have considerably more grip. Structural problems - deformation or sidewall bubbles - are more of a concern to me. Tires with those issues should be replaced immediately. Slow right down and check things out if anything feels unusual. Any tire that's worthy of driving at highway speed should have no vibrations. The older a tire is, the more frequently and thoroughly it should be inspected.

  • Golden2husky Golden2husky on Jun 28, 2016

    I have noticed that Michelin tires seem to be more prone to cracking that other brands. The MXV4s that I put on my station car had cracking between the treads after 7 years of being outside. Still had tread life but they failed inspection. Funny, my Michelin bicycle tires did the same thing...

    • See 5 previous
    • Turbo_awd Turbo_awd on Mar 30, 2018

      @VoGo Agree - only drive Michelin these days. We don't drive that much, but I always get highest quality Michelin tires. This doesn't mean I would throw away other tires in good shape, but when it's time for new tires, only Michelin. That might change if/when I actually get to a track sometime and look for tires that are more suited to that scenario.

  • FreedMike This article fails to mention that Toyota is also investing heavily in solid state battery tech - which would solve a lot of inherent EV problems - and plans to deploy it soon. https://insideevs.com/news/598046/toyota-global-leader-solid-state-batery-patents/Of course, Toyota being Toyota, it will use the tech in hybrids first, which is smart - that will give them the chance to iron out the wrinkles, so to speak. But having said that, I’m with Toyota here - I’m not sold on an all EV future happening anytime soon. But clearly the market share for these vehicles has nowhere to go but up; how far up depends mainly on charging availability. And whether Toyota’s competitors are all in is debatable. Plenty of bet-hedging is going on among makers in the North American market.
  • Jeff S I am not against EVs but I completely understand Toyota's position. As for Greenpeace putting Toyota at the bottom of their environmental list is more drama. A good hybrid uses less gas, is cleaner than most other ICE, and is more affordable than most EVs. Prius has proven longevity and low maintenance cost. Having had a hybrid Maverick since April and averaging 40 to 50 mpg in city driving it has been smooth driving and very economical. Ford also has very good hybrids and some of the earlier Escapes are still going strong at 300k miles. The only thing I would have liked in my hybrid Maverick would be a plug in but it didn't come with it. If Toyota made a plug in hybrid compact pickup like the Maverick it would sell well. I would consider an EV in the future but price, battery technology, and infrastructure has to advance and improve. I don't buy a vehicle based on the recommendation of Greenpeace, as a status symbol, or peer pressure. I buy a vehicle on what best needs my needs and that I actually like.
  • Mobes Kind of a weird thing that probably only bothers me, but when you see someone driving a car with ball joints clearly about to fail. I really don't want to be around a car with massive negative camber that's not intentional.
  • Jeff S How reliable are Audi? Seems the Mazda, CRV, and Rav4 in the higher trim would not only be a better value but would be more reliable in the long term. Interior wise and the overall package the Mazda would be the best choice.
  • Pickles69 They have a point. All things (or engines/propulsion) to all people. Yet, when the analogy of being, “a department store,” of options is used, I shudder. Department stores are failing faster than any other retail. Just something to chew on.