[mark houghton]

Originally Posted by zakthor

I'm driving stock 7 and 8 and my car is heavier. Tire calculator says I would drop 2psi if I switched to 8 & 9 on my car. Right now the tires feel sticky and the turn in is so hard that I can't tell what the tires are doing. Really feels like rails but my critical mind says the limit must be close.



Close enough. Aren't you running bigger tires than me?

But...

Question Mr. Merk raises is about this tire and its stiff sidewalls.

For autocross I can look at tire temps but for street driving my primary goal is tire life. I just don't know how to adjust pressure for a particular tire, especially because these are so sticky.

I go looking on tire companies web sites they all say to use the manufacturers numbers. No surprise because saying anything different invites a lawsuit with zero upside. The wear bars are explained but theres nothing about those triangles except that they point at the wear bars.

I'd like to understand the what and why of street tire pressure and wear - my tiny dog brain imagines its simply car weight and tire patch area so sidewall doesn't matter except when cornering. But maybe its complex stuff. Maybe its a case where everyone just 'X around and find out' and then community develops a consensus.

Will say these new tires 'handle' unbelievably well compared to anything I've had before. They have transformed the car. I guess I should play with pressure but right now I don't want to mess with a good thing.

One technique I've heard of but never tried: Draw a thick chalk line across the tire tread and drive for a couple hundred feet, then look to see how even the line is worn away.