My tires still have decent tread but I noticed they are starting to crack from age. Is it time to replace or can I get a little more life out of them. Sidewalls look good. Thank you.

 

It depends in great part why they are cracking. Look up the date code, old is old, 6+ years is too old so they say.

Cracking can also happen when you air down and wheel on rough terrain like rocks etc... makes the tire flex, indent and even twist so that a newer tire can have cracks in between treads like your pics.

 

Where do you see Info that says 6-year old tires are not acceptable? Many (most?) vehicles on the road have tires older than that, especially low mileage vehicles, sports cars, exotics, etc.

 

Vehicle manufacturers recommend tire replacement at 6 years....::::> Tire-Aging

 

The same article says:

"Tire manufacturers recommend replacement at 10 years, regardless of tread depth."

I would go with what the TIRE manufacturer says. They know better, and they do the warranties.

So in summary, age does not matter. Condition of tire matters.

I have had tires last 2 years and bulge or tread separate, and I have had tires on a car for 18 years. All good.

And I have see the hairline cracks the OP is showing on the tires on many tires. All good. As long as the cracks were not deep, only surficial. This is NORMAL, from my experience.
Some tires develop these almost from new. But I do not guarantee anything, as that is only based on a few photos.

 

NHTSA states a driver is three times more likely to be involved in a crash caused by poor tire condition.

 

Irrelevant to this conversation.

Could be due to underinflation, overinflation, or you know, that big bulge in your sidewall you are ignoring, and nothing to do with what we are discussing.