do street tires lose grip as they age?

stevbd

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I've read conflicting reports on this. Do street tires gradually heat cycle and lose grip as they age? I'm using Michelin PSS for daily driving and track days, and they have about 20K miles and 10 or so track days. So they're well worn for sure but they still (barely) pass state inspection and have a little remaining tread.

Much to my frustration, I am consistently a couple seconds slower on these tires than I was when they were new. Everything else on the car is identical. They certainly feel like they have less grip, but I hate making excuses.
 

01yellerCobra

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I'm sure they do. Rubber hardens as it ages. Harder surface means less grip.

Misspelling brought to you by Tapatalk
 

tigerhonaker

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OP,

they're well worn for sure but they still (barely) pass state inspection and have a little remaining tread.

As you have said above you are driving on Worn-Out-Tires.

Replace them !!!


Terry
 

groundpounder

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I had a whopping 19k on my factory original P235 Pzero Neros. They were date coded to middle 2006. They were HOCKEY PUCKS by March of 2015. So hard. Scared the s#&t outta me on a wet January drive back from Phoenix to Las Vegas. Would have been great drift tires! From now on, new tires ever 5 years.
 

Champale

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Yes, they do age out after heat cycles and/or time in use.

You've gotten a LOT of use out of them it sounds like.
 

RocketcarX

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Tires are the only safety feature touching the ground.
High mileage tires are for pedestrian cars driven by soccer moms at or below the speed limit, a real car built for speed is going to require tires at least every 2 years and mileage compromises need to be kept to a minimum.
You should honestly be wearing the drive tires fast enough to basically require this schedule anyhow if you're still square.
 

waylander

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it's not only the fact that they harden - old rubber also cracks, especially if you experience more extreme climates.

IIRC most tyres should be replaced after 5-7 years (if not already worn out)
skidmarks.gif
skidmarks.gif
 

Juice

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You should get a 2nd set of wheels shod with DOT racing slicks.

I've driven lots of track miles on lots of different tires. There are some really good "street" tires out there that do well for HPDE. Until you try a set of slicks......

Just remember to store the slicks out of the light, DEFLATED. The soft slicks can crack in the cold of winter if left inflated. This is stated on the tire stickers on one of the brands I use.
 

Norm Peterson

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I've read conflicting reports on this. Do street tires gradually heat cycle and lose grip as they age? I'm using Michelin PSS for daily driving and track days, and they have about 20K miles and 10 or so track days. So they're well worn for sure but they still (barely) pass state inspection and have a little remaining tread.

Much to my frustration, I am consistently a couple seconds slower on these tires than I was when they were new. Everything else on the car is identical. They certainly feel like they have less grip, but I hate making excuses.
Mine aren't worn nearly as much as yours, about 50% remaining to the wear bars. But on the 11th track day and after 4500 - 5000 street miles they clearly aren't as grippy as they once were. Datalogged g's are 0.07g or so off what they were at track day #9, which was already a little off the lap time pace of the not-datalogged previous track day. Same track in all three cases.

This coming Tuesday I hope to find out if they dropped off any further. I'll need the predicted possible rain to either hold off or blow through sooner.


Norm
 

Sky Render

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You should get a 2nd set of wheels shod with DOT racing slicks.

I've driven lots of track miles on lots of different tires. There are some really good "street" tires out there that do well for HPDE. Until you try a set of slicks......

Just remember to store the slicks out of the light, DEFLATED. The soft slicks can crack in the cold of winter if left inflated. This is stated on the tire stickers on one of the brands I use.

While I agree that DOT slicks are AWESOME, they're bad to learn on because they "cover up" mistakes. A good set of street tires is best to learn on.

Just posting this for any novices who might come across this thread.
 

stevbd

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Thanks for all the replies. I don't mind being slower as long as I know why I'm slower. Norm, leave it to you to bring the data, much appreciated.

I agree R comps look amazing but those are kind of a slippery slope - more grip equals more suspension, more brakes, more wear, etc. I'm sure I would love them though.

Plus I kind of enjoy beating up on my friends in their BMWs with track tires, even in the corners, it drives them nuts lol.
 

kerrynzl

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Thanks for all the replies. I don't mind being slower as long as I know why I'm slower. Norm, leave it to you to bring the data, much appreciated.

I agree R comps look amazing but those are kind of a slippery slope - more grip equals more suspension, more brakes, more wear, etc. I'm sure I would love them though.

Plus I kind of enjoy beating up on my friends in their BMWs with track tires, even in the corners, it drives them nuts lol.

Learn to back it into corners like an outlaw sprintcar [this fixes understeer as well] :waytogo:

Seriously though, why don't you soften those old tyres [but do it properly]

You need to de-mount the tyres and spray it on the inside , and quickly re-mount the [before it evaporates] Let it evaporate right through the tyre.
If you're not using the tyres daily, also spray the outside and store in a large plastic bag [trash bag]

You can make your own tyre softener really cheap. The two ingredients are 8 parts of Toluene to 1 part Sodium Silicate.
1 pint in a spray bottle is enough for 50 Tyres.

One warning ....... It stinks, so store your tyres outside [in bags]

Years ago I was given a really old set of Goodyear GSCS tyres to race in a meeting that only allowed street tyres. So I softened them.

They stuck like "sh*t to a blanket", up until the tyres were worn down to the plys
 

Juice

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I agree R comps look amazing but those are kind of a slippery slope - more grip equals more suspension, more brakes, more wear, etc. I'm sure I would love them though.

With open tracking, anytime you upgrade anything on the car, you find the next weakest link to upgrade! lol
 

Boaisy

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When I had my 2012, and only 1 set of tires, I was changing to new tires at least once a year. The first set, the factory P-Zero's, were so worn, they started to expose the tire cord right after the track season was over.

Similar to this, since I don't have access to the actual pictures atm:
164342d1168832288-ot-tire-cords-showing-front-passenger.jpg


I decided to change them when it was off season, and the car started to hydroplane during a storm. It was fun, but not something I was willing to deal with every time it rained. I later ended up getting a track-only set, and a daily-only set. Helped extend the daily rubber out to a 2 year run.

The family also has a set of Bridgestones that were put on the IROC back when I was in college, about 10 years ago. Since it sits in the garage a lot, the tread itself hasn't worn down. However, when we do take it out, you can tell it doesn't have quite as much grip as it had when they were new.
 
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Norm Peterson

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Thanks for all the replies. I don't mind being slower as long as I know why I'm slower. Norm, leave it to you to bring the data, much appreciated.
Grip seems to be holding constant. But there are a few caveats involved.

1) Less time between track days
2) Slightly firmer damper settings
3) Less rust on the driver mod

Between items 2 & 3 I took two seconds off August's best time, with somewhat better consistency.

I did manage a mid 1.3x g peak. But nothing else above 1.28, and it was mostly an artifact of having to catch a little tailhappiness in the slowest corner on the course.

Next time (not sure when that's going to be) will see the damping being cranked up some more.


Norm
 

GriffX

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As a general rule, use a street tire not more than 6 years. The rubber hardens due to newly formed sulfur bridges between the molecules and ozone degradation. Ozone is formed from normal oxygen in the air and UV light from the sun.
 

eolson

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I was told that high performance tires lose their grip by getting harder after about 3 years or so. So I'd have to drive a good deal more to have them wear out after 3 years, because they usually seem to have good tread up to 5 years for me, since my car is a fair weather car, and not a daily driver. Erik
 

AndrewNagle

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I was told that high performance tires lose their grip by getting harder after about 3 years or so. So I'd have to drive a good deal more to have them wear out after 3 years, because they usually seem to have good tread up to 5 years for me, since my car is a fair weather car, and not a daily driver. Erik

One way to find out is push them to their limit in a controlled area and find out

I to often have plenty of tread on the tire after 6 years...
 

Thenorm

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I was told that high performance tires lose their grip by getting harder after about 3 years or so. So I'd have to drive a good deal more to have them wear out after 3 years, because they usually seem to have good tread up to 5 years for me, since my car is a fair weather car, and not a daily driver. Erik

its not so much the time as the heat cycles. every time you heat the tire up hot, new sulphur bridges (vulcanization) for in the rubber making it harder. I notice my bridgestone start to get harder in about 6 months, at about 50% wear. but with easy driving, or less often driving, obviously they'd last longer.
 

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