Yok A032, where do the cords start / tire pressure
 

I have a set of Yok A032s that have seen 10 days at the track. They are still gripping well but are down to and through the wear bars. The wear is even with maybe a bit more in the center. Not very much tread to be found in the center. How much farther until I get to the cords ? I would like to run them for 2 more days.
Also, I seem to be getting the best grip starting with 34 psi cold. All 4 corners get to about 40 psi hot. I have tried higher cold temp
(by cold, I mean the night before after sitting a long time) and they go up about the same amount but feel greasier. I have not tried starting
them lower. The car is a 944 S2 with coil overs, the rest is stock. Any advice on the pressures ? Certainly the even hot pressure at all 4 corners is a good thing I would think. Thanks, Nate

Hate to see a post go unanswered, so here is what I know. I run Toyos, and we run them until the cord is showing, and you can get a day or two after all the tread has gone easy, maybe Yok's are the same

Jim

Jim,
Thanks for the reply ! I think I will try the
2 days out and let you all know.
I have heard great things about the Proxis RA1s
and have a set on order. It's just quite hard to
get them through the normal channels.
Nate

Forgot : Jim, what pressures (cold / hot) do
you find works best for the RA1s ?
Thanks, Nate

I don't have them dial in and I race in the Toyo spec class, so you would tink there would be some agreement on the cold pressures. But I have been told anything from 30psi to 20psi cold. I have tried 30psi and found them to hard, sonow I am starting with 25psi cold.

I think alot has to do with driving style, and suspension, I have 23mm and 31mm rear torson bars, 31mm front and 27mm sway bars, and bilstein shocks, revalved by Smart Racing.

I prefer a little understeer, and the ability to induce oversteer with my right foot.

I did not notice where you are located but if it is in the Bay Area in CA, check out, perhaps even it you are not in the BA you will find it interesting. My car is the "unidentified" one in the "Thunderhill Pictues (follow the NEWS link).


Jim

<a href="http://bushwacker-racing.com/prc/" target="_blank">http://bushwacker-racing.com/prc/</a>

I ran A032R's all last year. The advice I was given (from a Yokohama engineer via a PCA Club racer using them) was to use 1 psi of tire pressure per 100lbs of car weight. So for my 3.2 Carrera, I was starting, typically, at 27-28 psi(F/R), cold. I was never overly concerned with hot temperature but whenever I checked they were around 35-37psi.
As to wear, I was below the wear bars when I replaced them; virtually no tread depth in the grooves, but still not at the cords. I did notice a blueish tinge to the rubber which I'm told is an indication the rubber is getting hard and less grippy.

I'm through my second set of A032 tires, and have gradually been dropping the pressure from 35/33 to 30/32, with about 36 hot. The A032's are designed to scuff the sidewalls a bit up to the little arrows on the sidewall, and apparently this is one way to check whether the pressure is right. With the rule of 1psi per 100 lbs, I seem to be in the ball-park.