How long are street tires usable and safe?

[wdfifteen]

Originally Posted by kochtools

I have 30 years of work experience at one of the world's largest tire manufacturers ... in R&D.

What do you recommend for owners of classic cars that don't get much use? My Speedster is kept inside under a cover if I'm not driving it and I drive it less than 1000 miles a year. Same with the 911 and 356 coupe, though they get more use, but not by a whole lot. Add the old truck and the VW and I should be replacing 5 sets of tires with 95% tread life every ?? years.

[A930Rocket]

I remember buying a used BMW 318is that had tires about 10 years old. The tires were hard as bowling balls and I could fishtail the car when pulling out. As soon as I discovered this, I bought new tires. That a new shocks made a world of difference.

[flatbutt]

MC helmet manufacturers say get a new helmet every 5 years. I've never done that. As for tires if they're holding pressure, no cracking and the wear bars are still good then I say you're good to go.

[matthewb0051]

I just had to get rears for my 996, fronts had a lot of tread remaining. Found some NOS tires in my size and model. One of them showed up to my house and was date coded 2010. I didn't see it but the guy at Discount Tire did and said they couldn't mount it.

I was able to send both back but that also made me get 4 new tires, which I was trying to avoid. I had Sumitomo tires that had been discontinued thus the search for NOS rears.

After the Discount Tire guy told me the date I took a long look at that one tire. It had a different hardness and color to it. Glad I didn't put it on now that it is 110 degrees everyday here for the last month.

[911 Rod]

Pull each wheel off and inspect them. You can't see much on the car.

[GH85Carrera]

Originally Posted by wdfifteen

What do you recommend for owners of classic cars that don't get much use? My Speedster is kept inside under a cover if I'm not driving it and I drive it less than 1000 miles a year. Same with the 911 and 356 coupe, though they get more use, but not by a whole lot. Add the old truck and the VW and I should be replacing 5 sets of tires with 95% tread life every ?? years.

Much of that depends on the usage of the tires. At concours events some owners will put on the original tires a car came with on their 1970s and 1980s cars. Those are just to drive onto the field, and not for a spirited drive in the mountains.

If you are just driving the car to the car show at reasonable speeds and no hard cornering, I really would not worry much about it.

I never get more than a few years from my 911s tires as autocross and track days are great for shedding the nasty unsprung weight of excess tread and brake pad thickness.

My wife's 2017 Macan still has the original tires on it. She only has 22,000 miles on the car. It stays in the garage when not being driven, and not driven in icy conditions at all, and only driven in rain when necessary. We will likely wait another year of so before replacing them. They are the ONLY part of the vehicle in contact with the ground and provide 100% of the traction to go, turn or stop the vehicle. Kinda important tasks.

[cockerpunk]

100% fine.

[Zeke]

I have 23 YO tires on the '44 Jeep and they look new. Of course in 23 years the thing has been driven less than 500 miles. It stays covered and buried under junk. I'm sure new tires would make for a better ride but there is no ride to begin with. Worst ever vehicle for comfort or handling. It's tantamount to a covered wagon.

[Scott Douglas]

^^^ I'm surprised you didn't liken it to a buckboard, Zeke.
Does that mean you have a top for it?

[URY914]

You may want to check the condition of your spare tire as well. I had a flat last week and had to pull out my 13 year old original spare and run it for a few days. Side walls had some cracks but it only had 12 psi in it.
I limped down the road to the gas mega store and pumped it up.

[Tobra]

I am as cheap as the day is long

NEVER have I ever cheaped out on tires. Have some perfect looking 7 year old tires on the 911 that are gone when I get the time to do so, and it is not getting over 55 mph until I do.

[Zeke]

Originally Posted by Scott Douglas

^^^ I'm surprised you didn't liken it to a buckboard, Zeke.
Does that mean you have a top for it?

Thought 'buckboard' at first. Didn't know if everyone knew the term. It is a buckboard.

[ted]

Agree 7 years is my limit if I can get them to last that long.
I always use tire covers on the Trailer and occasionally when the truck is parked outside too.
What a joke at the Goodyear store some tire jockey tells me that tires don't start deteriorating until you put air in them.
Really indefinite shelf life if no air pressure?

The race slicks get checked with a durometer to check if they have dried up and got too hard.
Between races they are stored in the coolest corner of the garage, coated with WD40, wrapped in Saran wrap and covered with a tarp. Plastic wrap stays on till it time to race.

[Tobra]

treat the tires with WD 40, interesting

[ted]

Originally Posted by Tobra

treat the tires with WD 40, interesting

Yeah surprised me, but my race shop suggested it.
I only use wd40 on the race slicks in storage.
Does it help maybe, just trying to get the last heat cycle out of them.
I've tried all the messy tire softeners on used slicks, rather not mess with that.

[kochtools]

This discussion is a really interesting insight into the the common level of understanding related to tires and materials.

A modern street tire has 70+ distinct materials … each of them play a role. In totality, I would argue that a tire is the most advanced composite structure in terms of composition and use-case … non linear in regards to age, temperature, deformation rate and deformation amplitude.

The topic of aging is only partially about the tread and its traction attributes. From a safety perspective, the topic of rubber to belt or rubber to body ply adhesion is equally important and a significant contributor to the 10 year guidance.

I will not address spraying wd40 on your tires … unless you have any idea of what’s in the tread compound to begin with and the associated material science, you are operating in the realm of witchcraft.

[ted]

Originally Posted by kochtools

I will not address spraying wd40 on your tires … unless you have any idea of what’s in the tread compound to begin with and the associated material science, you are operating in the realm of witchcraft.

With all of your 29 years as a tire materials scientist what have you seen that does soften or extend tire life? I'd value your educated input.

I try to keep air and the sunlight off of the slicks.
WD40 was suggested to me by a longtimer short track oval racer, they have some seat of pants experience with tire management.

This guy is wearing a witches' hat, you can hear it in his voice.

[jhynesrockmtn]

My wife's 2015 Macan had 2016 date code Michelin's on it. The tread was on the margin. We run snow tires in the winter so they didn't see too many miles but on a long trip last summer they felt hard and the ride was tiring. I just put new Falken's on it and did a long trip this last weekend. Way better. I would think 10 is reasonable if good tread and they are well cared for and stored inside.

I just put new tires on a 914 I bought last summer. The guy at the tire store couldn't believe I was tossing them. They look brand new he said. Yeah, but they are over 20 years old. Oh, yes, that makes sense.

[David]

My personal rule is 5 years but I drive everything like I stole it.

I'm like a kid with a new pair of shoes when I get new tires so I don't have the patience to go more than 5 years anyway.

[cockerpunk]

i dont know of a racing series that allows tire treatments, in dirt track they certainly dont. i dont think any road racing series allows tire treatments either.