When do old snow tires need replacing?

2011 Suzuki SX-4 205/60/16 - current snows made September, 2014, so 9 years 2 months old. Tread is fair.

2016 Mazda6 225/50R18 - current snows made May, 2015, so 8 years 4 months old. Tread is fair, as you'd expect.

We both work from home so driving is not critical. Probably fewer than 2,000 miles for snow tire season on each car. She who drives the Suzuki is a very gentle driver, neither fast or daring. I drive the Mazda6 more enthusiastically.

I'd say the tread is okay on both, but I'm concerned about the age of the tires. Tires are stored outside in a shed out of the sun, no temp control. We're in Colorado so very dry and the snow goes away quickly so don't need good slush capability.

I don't want to buy new tires if I don't need to, but I really don't want to blow a tire, slide off the road, and die in a fiery wreck. I'd get an SUV if I wanted that!

BoulderG said:

but I really don't want to blow a tire, slide off the road, and die in a fiery wreck.

IMHO you just answered your own question. 

"Work from home, driving not critical" means just get a good set of snow capable all seasons and leave them on full time. Snow tires are for the times where there's fresh snow/ice on the road and you absolutely need to get somewhere. Outside of that they don't do anything well enough to justify keeping two sets of wheels and tires around.

To directly answer your question, I would struggle to trust any 8-9 year old tires, even less so ones that spend 3/4 of the year sitting not being used.

What does the rubber look like and feel like? Any dry rot? Is the rubber still soft? On the use case, do you have kids that will be riding in the cars? How far is the hospital? 

Eh, irrelevant. They're old. Time to replace them. I would think you can probably get away with all seasons on one of them. Just drive the other one when snow is in the forecast. 

I throw them out after two years. The second season has noticeably less grip than the first season.  The third season, they are as hard as all seasons and not worth even putting on the car.

My largest concern is ice, we have a daily thaw/refreeze cycle that is a recipe for ice formation, and as much salt as they put down it is sometimes not enough.

Pete. (l33t FS) said:

I throw them out after two years. The second season has noticeably less grip than the first season.  The third season, they are as hard as all seasons and not worth even putting on the car.

 

My largest concern is ice, we have a daily thaw/refreeze cycle that is a recipe for ice formation, and as much salt as they put down it is sometimes not enough.

They do degrade over time, but I've never found snows to degrade that severely in a couple of years, at least not with Blizzaks or Hakkas.  I have seen some 5+ year old, rock hard snow tires though. 

I have found a lot of tires harden up a little on the tread surface when they sit, so it takes a little driving on pavement to wear some of that surface layer off and get the grip back.  I often end up switching to snows based on temperature, so they see enough pavement driving to clean them off before they see snow. 

8 and 9 years is too long for any tire you care to get maximum performance out of.

The solid consensus is "Don't use these." Thank you. I won't.

Our summer tires are All-Seasons from Discount Tire - Sx-4 has Yokohama YK740gtx and Mazda6 has Continental Control Contact Sport A/S.

Surprisingly, the guy at Discount Tire (different branch from where we bought the tires) thought pretty highly of both models as All-Seasons and wasn't pushing us to buy snow tires.

If weather forecasts are correct, we'll know by Monday...

Literally going out to swap the snow tires on my wifes car now...

My Fiesta has what's left of the original 200 tw summer tires on it now.  I'll be lucky to get it into the garage to swap on the snow tires.

I usually get 3 winters out of a set of Blizzaks, and that's running them from November through March/April.  The performance in that third winter is never great, even with bagging them when not being used.