Hey...so is it true that a worn tire is not as sticky?

I keep hearing that when the tire is close or past the wear bar...it no longer performs on dry conditions as good as a non-worn tire. Is that the case of the S02's?

My rear Toyo's are down to the wear bar...and I had them replaced at lunch. I could swear they felt more grippy when they were new.

My stock tires are also worn to the wear bar...I was wondering if I should use them at a track event...or are they not going to hold thier ground?

Thanks a million...

 

I really noticed that my OEM S02's got real 'loose' when I got near the wear bars. I could slide the rear pretty easily and loved the mini-drift when doing U-turns on Westheimer during lunch. I think the people waiting at the bus stop enjoyed the 9k rpm show.

I am also getting near my S02 PP wear bars, at 18k miles . Theses tires are also letting me spin/slide pretty easily.


Tex_s2k and I feel that the OEM S02's provide more grip than the Pole Positions(PP) period. The PP's are supposed to have the UNI-T technology which provides a grippier inner compound that is supposed to compensate for tire wear. With my experience, new tires always have provided the best grip and diminish with mileage.

I still haven't seen your powdercoated OEM wheels. Put them on next weekend so I can see!

 

joe_s2k,

You got it bro...as long as it's not raining...I'll stick on the stock wheels for you to check out. You know what? I wanted to powercoated them that "charcoal black" color of the Volk's you saw at Carboy. But...I couldn't find a match at the powdercoating factory. Oh well...it's all good.

I'm also supposed to have my nippon exhaust delivered before this weekend...but MG Racing hasn't called me to tell me that the exhaust has cleared the Atlanta airport customs department. Sheesh...

 

Most tires lose grip the more heat cycles they are subjected to (heating, cooling, heating, cooling,..etc...).

 

Bieg,

Wear and tear because of heat cyling eh? Thanks for bringing that to my attention...I would have never thought about that factor...

 

Heat causes the rubber to harden, and thus gripping less. Very noticable in racing (bike) tires which change a lot after a race or practice session. I've "inherited" some friends slicks that still feel exteremely grippy to me but are no longer good for racing since they have hardened after a couple of practice runs.

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[grey]2000 S2000 - 1998 VFR800 - 2000 Atos[/grey]

 

Bassman is right.

It's not the "wear" (loss of rubber) that causes the tire to lose grip, it's the amount of heat cycles the tire has been through. The cycles harden the rubber compound.

You could spend a hour lapping on a track and use up most of your rubber but the tire will still have good grip the next time you use it.

If, however, you normally do alot of highspeed driving around town (like driving to work) you will probably notice that your tires will lose some of their performance long before you actually run out of tread.

 

Heat cycles harden softer tires noticeably. Harder tires get harder with age but it may be subtle. The new S-O3 PP is considerably harder than the OEM S-O2 (220 vs. 140 treadware rating) when new but I suspect the difference with age will vary greatly between the two. The S-O3 contains some compounds to retain more of the original softness of the tire and a second grippier compound to compensate for the eventual loss of the outer tread layer.
When an S-O2 and some other ultra-performance tires are driven enough miles they give up much of their original dry traction and have little or no wet abilities.
It's a trade off for street tires. Some are willing to give up ultimate dry performance for wet traction. Others are willing to sacrifice most wet performance (and mileage) for outrageous dry handling like the BFG G-Force KD.

 

During heat cycling the "oils" in the tire are driven to the surface of the tire and the soft rubber is "spalled" off. This is why you see all the tire chunks at race tracks in the corners. When the oils are depleted (i.e. cooked out) the rubber becomes less compliant and therefore the tires will get loose as they are actually harder (less compliant). To really see this effect take a look at any sport bike tire if the guy leans the bike and pushes it...you can literally see the oil on the edges. On sport bikes a lot of guys actually remove this oil so the don't bif it before the tires get hot again. Thermal cycling is the death of stickies.

 

When I roadraced bikes, it was real easy to tell when the tires would change, even between races. The Dunlops I used were good for about 3 heat races, but would lose their grip after about 5 hard laps. With some experience, it was easy to tell when it was time to get new rubber. I remember when I first started racing I thought, "I have plenty of tread left" and went out and slid the heck out of the bike only to come in and find my lap times were around 5 seconds a lap slower than when I was taking it easy the day before.