Tires: How old is too old for basic use?

I'm aware of the conventional wisdom that tires more than 4-5 years should be replaced, but I'm hoping for a practical dialogue to better understand the reasons for this practice. I have a set of 19" lobster forks shod in a set of Michelin Pilot Sports with 2006 date codes. The tires have excellent tread, but I'm sure the rubber is quite stiff. I certainly wouldn't track them in an HPDE, but what about a trip to the autocross? Toodling around town? Highway speeds? Is the risk a sudden catastrophic failure, or is it more about a greasy, hard rubber sensation, longer braking distance, and squirrelly handling? Combination of these? Something else? I'm trying to understand the specific reasons to retire old rubber. I don't really plan to run these wheels until I get them refinished and new tires fitted anyway, but this forum is a deep well of knowledge, so I hope to learn something new.

I wouldn’t drive on tires older than 6 years old. Same goes for my family. I replace tires long before then normally. Older tires affect braking and handling.

https://www.thedrive.com/article/518...rs-fatal-crash I'm going to pick up a car tomorrow with tires from 2013. I'm not worried about driving it home but tires will be the first thing done. Autocross, no way.

I bought my "still" new to me 1999 back in November with full tread tires but from 2016. They are hard, rough, and feel like sliding around on plastic. I only have them on still as getting items sorted out - plus going to swap to new wheels shortly. But there's no reason to save a few bucks and drive unsafe tires.

Tires from 2006 are 17 years old, more than 10 years past any reasonable lifetime for a Porsche tire. Don't use them at all.

We�d swap out or tire inventory every year when I worked for Lexus back in the day and we couldn�t sell tires older than 3yrs old from vendors. I would probably consider them as a spare and limited highway use. Honestly the sidewalls will be more susceptible to damage due to put holes and alike. I don�t think tire separation would be an issue at low speeds but wouldn�t do much if any highway travel.

Tires harden as the rubber begins to lose the volatile gases that affect the tire's compound. This generally starts as soon as the protective coating is scrubbed off at first use. The rate of rubber hardening can be affected by the type of exposure. A tire with lots of miles on a car that sits outside, exposed to temps and sunlight, may easily be toast in 4 years, where a tire with lower use stored in a protected garage might logically have a longer safe life. My 996 bought last year came with Pilot Sports with 2015 date codes, but were purchased and installed at a Michelin dealer in 2018, garage-stored, and have about 5000-6000 miles on them. They still stick like they should, and I consider them completely safe for road use, but will likely replace in 12-18 months. It's also worth noting that the normal standard for HPDE events is a tire manufacture date of 4 years or less. Since this age standard applies to high speed events, clearly tires don't disintegrate at 4 1/2 years. Just another perspective....

Certainly wouldn't canyon carve or track an old set of tires. But don't think for a minute you aren't at risk locally on the hwy or street with either less grip or rubber that is brittle. good rubber + good brakes = good outcomes

Some manufacturers age quicker then others my Michelin always start dry rot much earlier then my continental on the same car I tend to go max 7 years road use 3 on tracked

Tires over 6 years old are only good for "burn-outs" , " drifting", and " lots of smoke"....nothing else....the older the more dangerous..

From Michelin's web site: " While most tires will need replacement before they achieve 10 years, it is recommended that any tires in service 10 years or more from the date of manufacture, including spare tires, be replaced with new tires as a simple precaution even if such tires appear serviceable and even if they have not reached the legal wear limit."

You can buy a Durometer gage from various racing parts and equipment sites, you can see how hard the tires are compared to new. I've seen 2 year old tires that hard already dried out and were hard as a rock.

Interesting thread here: Tire Date Code - Sale Date - Rennlist - Porsche Discussion Forums Kind of like oil threads, many of them out there.

I've got a set of 10 year old winters that my Turbo is currently sitting on in the garage, but my plan is to replace them this year. I'm trying to replace at 6-8 years, but since I basically only do limited driving on all my cars, I'm okay keeping them on a teeny bit longer...if they look good and feel good and check out. Any cracks or anything - gone.

The tires on my Cayenne are about 12 years old. They are rather hard, somewhat out of balance, and take a set when cold. I plan to replace them.... eventually.

Thanks for the discussion, but I'm not really looking for more affirmation that old tires SHOULDN'T be used; I'm asking about the science behind the WHY. Perhaps my initial question was inartful. I know the rubber gets harder over time; there seems to be no suppleness in these tires at all. I literally put them on because I needed to put the snows on the Boxster while the 996 has been out of commission on the near-eternal UAOS install project (due mostly to time away for work). I put the Michelin-clad lobsters on just to roll the 911 out of the garage and pull it back in onto the lift. One of the wheels is slightly bent anyway. I plan to try and get that straightened and then get the set powdercoated in champagne gold before re-cladding them as a secondary set to the factory twists. Since the consensus seems to be that the old tires are at risk of catastrophic failure if I were to spend an afternoon screwing around on them, I'll resist the temptation. Last thing I want to do is end up in the ditch or into a canyon wall. I did a little more digging independent of the forum and found some interesting tidbits, including a note that the tires on the Carrera GT that took actor Paul Walker on his infamous last ride were at least 9 years old. https://www.edmunds.com/car-maintena...our-tires.html Even some ambulance chasers have opined on this: https://www.wfirm.com/tires-expire-in-six-years/ https://www.continental-tires.com/ca...age-age-repair

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Well not sure of all the science, but can tell you my RV in Phoenix covered storage for 6months a year and 4 months in the Cali desert Glamis dunes, dry rots Michelin tires 10 times as fast as my tires in the NE. In just a few years a checker board of cracks become very apparent. Granted these cracks are more or less on the surface outer rubber to start. But get deeper every year. I also treat the tires with a quality rubber preserver every month to try and extend their life and ward off more dry rot. I've had tires garage kept in Florida, except for relatively short local rides,, look and feel perfect for way over 5 years... My point, (and the science) the sun's rays are #1 killer for short lived rubber and plastic. As is the dry heat of AZ. Location is everything when it comes to tire longevity. jmo

Now decades ago when the US had thousands of soldiers and families in Europe, particularly German there were numerous tire sidewall blow out accidents on the Autobahn to include fatalities with imported cars from the US. People were not only driving non-speed rated tires too fast, but also dry rotted. They quickly implemented a very strict tire inspection program. Don't remember an age criteria, but any signs of dry rot tires had to be replaced before you could pick up your car. There was also a minimum speed rating higher than the US. That said tires stored out of the sun (UV) with temperature and humidity control can easily last beyond the 5-6 year rule of thumb. As already stated tires start out gassing immediately which is why they have a protective coating. Hardness, or loss of grip would be the first symptom quickly followed by cracks between the tread and sidewalls.

Ozone also does a number on tires. Ozone can be created by sparking at the brushes of electric motors, so keep that in mind when selecting storage places.

It�s really about belt separation, as the rubber ages it becomes more difficult to adhere to the steel belt in the tire case. When the tire becomes hot from flexing when driving at speed, the connection between belt and tread becomes weak. The tread will separate from the casing and that�s where problems happen. I have had this experience 5 times in my life, all with tires over 10 years old that had very good tread and weren�t dry rotted. It starts with a slight vibration and quickly goes to a lump in the tire. Most times the tire just blows out in that area of separation, but I had the complete tread separation one time that just left the steel belt casing full of air. Spare tires inside or under the car will do the same thing even if they haven�t been used at all. If you are just putting around town and not getting the tires hot, they more than likely will be fine. I have 30 year old tires on a car that has been stored inside and they are not cracked or out of round. They travel less than 10 miles per trip, and don�t get driven over 60 mph for any extended time. They are definitely harder than they were when new, and horrifyingly dangerous when it rains( got caught in the rain one time) but they still are in balance and have no tread separation. If I started driving it more regularly they would come apart in sure.

Friday Night my buddy Randy was over helping build some UAOS's , then we went to eat Mexican and I drove his 1999 996 we had built the engine in 7 years and 37k miles ago 3.4 to 3.8 LNE Nickies, JE, Carrillo, headers, x-pipe, muffler by-pass, CC inserts .. UAOS ect........... The car Screems !! We had just gotten through talking about him getting some Track tires for the up coming Track Day,( with UIDS) ..... His car hasn't been driven a lot in the last 5 years ( double lung transplant) , most of the 37k miles on the new engine was done in the first two years after the rebuild....so the tires are quite old... He left my house and got on I-22 headed back home ( yea he was ripping it) then this happened...the right rear tire passed him as he was slowing down..

That�s typically under inflation or a flat tire that went unnoticed. As opposed to the belt separating from old tires. I know both, and have driven on a flat low profile tire at speed without knowing. I am presently installing aftermarket tpms systems on all of my cars with low profile tires, because of this and being tired of checking them before I drive. Not much visual warning on a tire like that when it only has 10psi or so.

Yep, and the reason I have TPMS on my 99 also.... I think Randy just had the wheels powder coated last week also...but it could be his other set....I'll have to ask him the details, we haven't got down to the details yet....he just posted the pictures and said he had a blow-out....I didn't notice anything when I drove it earlier, but I wasn't on the Interstate either...

Porsche says 6 years. That's what I follow. I've seen Michelin and Pirelli say 10 years. I always time out my sports car tires prior to wearing them out. But getting a couple of additional years out of a tire is not worth the risk to me when driving next to trees at 45mph. Michelin: https://www.michelinman.com/auto/aut...need-new-tires Pirelli mentioned it here: You Tube

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YIKES!!

I just talked to Randy and his tires are 7 years old, the wheels were just powder coated last week and he checked/adjusted the pressures right after he put them on..... He said he was going over 100mph when it blew ..lol.....he was showing off with a hot rod truck...lol

Looks like that could've ended VERY badly.

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For sure !! We had just talked about him getting some fresh Toyo r888 tires for his upcoming Track Day just hours before this happened....I don't see how the sidewall stayed on the rim, at least it protected his newly powder coated rims...lol I recommened he get a TPMS kit also...

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This ^^ But the tires (or the car where they are installed) have to be well kept, in garage, and the tires well maintained with their pressure according to specs.

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Suggestions on which kit can be used/retrofitted to MY99?

Here are some I’ve thought about getting to go along with my Harry’s Lap Timer & GoPros: https://www.gps-laptimer.de/compatibility/ios They work with iPhones. There is another page with Android accessories. I hate factory TPMS systems because they all fail too soon. I recently bought an Autel TPMS diagnostic/programming tool which was fairly expensive that is still a pain to use. I’m glad my 996 doesn’t have a TPMS. I’d only use one at the track.

I think they still have valve caps that can show red and green on tire pressure once set

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I went with this cheap wireless solar powered TPMS...It's easy to install , almost maintenace free,and totally reversable if you don't like it... The display sticks to the windshield above the mirror ( or wherever you want) is solar powered ( also has a USB phone charger, but I have only needed it once in 5 years ) . It comes on automatically when you enter the car ( vibration sensitive) and turns off automatically ( after a couple of minutes when stopped) ... The tire pressure seems very accurate but the tire temperature is not really relative since the Sensor is on the valve stem and not in the tire... When you first enter the car it displays the pressure of the last signal when stopped, then updates after you are moving above 5mph... The Sensors just screw on to the valve stem and have replaceable button type batteries.. The batteries last about 4 years if you use good quality fresh batteries... I recommend using metal valve stems ( the type used in factory TPMS but without the Internal Sensors) , I don't like the idea of using these with rubber valve stems...they are just too heavy for rubber valve stems.. Also use a balancing weight opposite the Sensor.. ( I forget how much they weight but is not insignificant) .... If you decide you don't like them and want to go back to manually checking tire pressures every day, you can quickly remove the whole thing and "Gone in 60 seconds"...but trust me, I won't go back to manually checking pressures every day but I would buy a higher quality one that works just like this one if availible... Sensor technology: Pressure sensing, temperature sensing , motion sensing, battery conservation, bluetooth transmitter , replaceable battery ...Display technology :: bluetooth reciever , solar power, usb power, vibration detection , display memory, rechargable li-ion battery..ect...that's a lot of tech for $30 , I would pay more, especially if I thought it was a higher quality/more reliable, but mine has been flawless and more expensive versions are not avalible.. Metal valve stems ;; https://www.ebay.com/itm/28470764698...3ABFBMgoPazsVh Made in China but isn't just about everything now?? https://www.ebay.com/itm/38507054783...Bk9SR6q_j8fFYQ

3 questions for you experienced smart guys on the spare tire. 1. Is the spare tire size the same on the C2 as the C4S, turbo and GT3. 2. If they are different sizes, will they all fit on a C2? 3. Will any fit over a big brake kit?

Yikes! Even 7 years seems like a very long time for a tire in service. Just think about all the crap it needs to put up with. Temperature changes, g forces, potholes and road debris.... I just picked up some fresh PS4S rubber and was happy to see production codes of 0722 for front and 2122 for rear, so very new tires. With the amount of miles I do I don't see time ever being an issue. I got 24k miles out of my rears in 2 years on General RS Max. Fronts can go even longer Turns out they are owned by Continental and often made in the same factory as continental rubber! Just depends which mold they use. Relative to how much money we spend on modifying, rebuilding and just maintaining our cars, tires are not that expensive and probably the most important thing. It's the only thing keeping that $25k+ motor on the road and not the ditch!

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I bought those and used them for a while about 5 years ago. The problem I had is that the plastic cap became very brittle and finally broke, letting all of the air out of the tire. I bought 5 U912 TPMs systems that have hard wired displays that are small. They have internal sensors with valve stems so yiu haveto dismount the tires. They seem nice for $60 and they are accurate.

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I used one of those sensors that screw on the valve stem on my Mazda. They worked great. However, the cheap brass locking nut that screws up under the sensor corroded very badly in about 1 year and bonded to the valve stem. I was able to force the sensor off, but I couldn't get the brass nut off, it kept unscrewing the valve stem. Finally had to use a dremel to split the nut off of the valve stem. I only slightly nicked the valve stem, so it's fine for now, but overall it was a disaster and I took them all off. I'll have to find ones with quality materials if I ever go that direction in the future.

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yea I left those brass locking nuts off....I didn't see the need for them ( thieft deterent?) and figgured they would be a PITA ...no issus without them in 8-9 years

How many people here "actually" check thier tire pressures before driving thier car "every time" ??? Tire pressure is THE most important safety thing you can check on a car .I find extreeme satisfaction in glancing at the tire pressures several times during a fun trip ....