Tire Recommendation

[Chuck Miller]

Need some help guys...

Been driving on Bridgestone S-03 street tires (205x55 - 225x50 F/R) for over 2 years now and I've found a couple of things...

First, the attrition is a little nuts at under 7000 miles for rears and about 15000 for fronts...
Next is a more recent concern... after the rebuild, I driving into and out of turns MUCH faster and the S-03's start building pressure and going off. Then I bleed them down and cool'm off and their OK again... (had to do this twice on our Ojai fun run) I would seem that I shouldn't have to manage my street tires like my race tires...

Anyway, most of you know my set-up and how hard I drive... I usually run about 33/35 F/R and after a hard run they'll start going off like a race tire ... and when I check'm they'll be up about 36/43... Now, if this was the track I could compensate with the pressures before a run group etc... however on the street I can't start'm too low or I'll be in trouble the other way...

So, I guess my question is ...
Is there another quantum leap in street tire technology since the S-03s in both longevity and stability?

Cheers,

[larry47us]

Chuck:

Tire pressure is ALWAYS going to rise when a tire heats up. It is just a matter of physics. That is why they always recommend that you measure the pressure on your tires when they are cold. A 10% rise in pressure when they have been driven - even not being driven hard - isn't unexpected.

Has this been taken into account by tire manufacturers when they tell you to fill your tires to 32 PSI? I would think so, since they say that the COLD inflation pressure should be 32 PSI (or any other pressure.)

Are you just being a bit too concerned about your tire pressure? Are you saying that you feel a significant difference in the way the tires perform when they are warm?

larry

[Chuck Miller]

Yes to the second question Larry...

Don't care what they build to ... it's relative to many factors anyway...

No, the point is when I work them hard and they heat up and build pressure their performance falls off considerably...

I would say I'm rolling into and powering out of corners about 15 to 20% harder/faster then I was before the rebuild...

Before, I thought the S03's were the absolute best street tires I have ever been on .... However now that I've upped the ante I'm afraid the honeymoon is over...

Looking for something better in a 15"

Cheers,

[fourteenten]

Chuck,

I found the same thing with the S-03's, during my occasional trackday the car feels like driving over balls through the corners after a few hours. Sliding and screaming of the tires is fantastic though, but indeed you lose a lot of grip. And it's waering out the sides much faster. I start of with 30 psi f/r. On the other hand, in the wet they are superior.

Cees

[Chuck Miller]

Well, there'ya'go...

Dank u zee Cees

[spydr32000]

Chuck as you would well know the next step up in tyres is the 'R' rated range of tyres from Bridgestone, Dunlop and Yokohama. These are the three we have had the most success with, we have found they like to start at 28psi front and rear, and will work upto aprox 33-34 psi. With the SO3's you could try using 30 psi to start with as the have a softer sidewall and need more support(pressure). We have used these pressures in cars competing in track days and tarmac rallies alike with similar results in grip and tyre wear etc.

[Chuck Miller]

Thanks Mike,

Have been hesitant to start them that low but you're right ... I tried that strategy the last bleed-off on the fun run and it kind'a worked...

Have another set of 7 & 8's mounted w/Kumho Ecsta DOT R tires in the garage for track days ... Was hoping there was something in-between race race rubber and the S-03's...

I might just decide to bite the bullet and run DOT race tires on the street like a few of my friends do ....... and stop whining...and be done with it...

Man, do the tire companies like us or what?

Cheers mate,

[andyjboy]

How about filling them with nitrogen rather than 'air' - less variation with pressure vs temp?

Some of the high performance tyre shops over here offer that facility.

[HarryD]

How about filling them with nitrogen rather than 'air' - less variation with pressure vs temp?

Some of the high performance tyre shops over here offer that facility.

Looking at how temperature and volume are related to gas properties, (ideal gas law [PV=nRt] for you science types) I would expect N2 to have about 3% less change in pressure(P) due to temperature (T) change. This is because a quantity of nitrogen weighs 28 units (n) while the same quantity of Air weighs approximately 29 units (n) and the total volume gas (V) in the tire is effectively unchanged.

[andyjboy]

What I should have said was dry nitrogen - most 'air' used to fill tyres contains a fair amount of water vapour which, when it gets hot, will have a more marked effect on the tyre pressure...