Tim Taylor wrote on 11/24/2019 9:42 PM:
"The NHTSA recommends that tires be replaced every six years regardless of the number of miles driven. Proper inflation is the Holy Grail of tire maintenance. Too much or too little air in your tires is guaranteed to cause you trouble and uneven or excessive wear over time.Dec 17, 2013"

The current recommendation is not so strict (2017):

"As tires age, they are more prone to failure. Some vehicle and tire manufacturers
recommend replacing tires that are six to 10 years old, regardless of treadwear.
You can determine how old your tire is by looking on the sidewall for your DOT
Tire Identification Number (TIN)."

https://www.nhtsa.gov/equipment/tires#topic-aging

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Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1