I'm getting a new set of rubber all around but they won't be in and on before a DE I'm doing in a week. My question is regarding grip on Michelin PS2 rears that are worn. The tread is not down to the 2 middle wear bars, but the innermost wear bar is now showing (below).

My only question is whether the tire will have noticeably less grip in this condition? Does the grip level on the PS2s decline in a linear fashion? Or drop off?

Just curious to hear from anyone who has run a PS2 at or near the wear bars on track.

- of course I have to pass inspection with these first -

Thank for any feedback.

DRP

 

Actually a worn tire (not corded, of course) will adhere better than one with more tread in dry conditions (think slicks, tires that are shaved, larger contact patch, etc.). Wet conditions; a whole different story. Pray for sunny sky's and have fun! Best,

 

I think your ok for one more event.

What tire you waiting for?

I'm putting on the new Michelin pilot sports for a DE this Friday.

Also adding bilstiens and control arms. The slippery slope has started.

 

One event might eat through the inboard side of your rears. Keep an eye on them as you could thread them in one day at the track.

Jason

 

Looks just like my ps2s before the last track day. Both corded on the inside edge by the end of the day. The traction was OK- maybe down a bit at the end.

I had some p zero rossos that performed poorly at the end. The ps2s are much better at the end of their tread.

It is easy to miss the wear on the inside rear. Don't forget to check in between sessions.

Have fun!

 

I agree. Very easy to miss the cords on the rear.

 

Worn out rear tires can spin even at slow speed on wrong moment . Placing the car on the track I woudn't take the chance . Too much to risk .

 

I think yrallis is right here.
Check out this link:

http://www.youtube.com/watch?v=1akRyPHTogA

That is a vid of my car with PS2s with 12K miles on them. The driver is Mark Daddio. Google him to see how many national championships he has won in Solo. He couldn't even drive my car with those tires!!

 

+1 I'm putting the Pilot Super Sports on as well. Less $ better performance all around. I love the way Michelins handle. Always have.

I'm hoping the new rubber will be significantly quieter on the road.

Let me know how you like them. Good luck.

DRP

 

Fully agree with Steamboat but make sure that the tyres are evenly worn and no flat spots.

When you finish this set of PS2, go for a new set of Pilot Super Sport. They are much better that the PS2

 

Will do.

 

I agree with the others that say you will be fine (as long as the cords are showing).

 

you need more camber in rear plus in the future it helps to use cheaper tires as you can see now what happens to them.
it is madness to put on $1600 set of tires to kill them on track. last shaved fronts RA1 toyos i got were $140 apiece. Set of rears RA1 did cost me $380 shipped. it takes time and effort to shop for tires but unless you ready to pay retail it is worth additional effort. complete set of R888 I have in basement did cost me under $800 shipped.

those tires you got still have life for 1-2 events depending on how fast you will go. when PS2 will start to melt you`ll see that you have got 100% out of them. so far they just getting edges scrubbed. you can keep to drive on them until you`ll see cord. then depending of what rims you got - consider something cheaper, for street tires in 19" - RE11 may be, if you can go 235/275 or 235/285 in 18" - you got Z1 star specs, r-s3 hankooks, etc. there are plenty of decently good tires in the segment of <$1K per set.

 

That is a vid of my car with PS2s with 12K miles on them. The driver is Mark Daddio. Google him to see how many national championships he has won in Solo. He couldn't even drive my car with those tires!![/quote]

Just as food for thought and not to start a p-contest, I would submit that before a solution can be affected, it is important to understand what the underlying problem is and in this case, it probably has little to do with tires that had 12,000 miles on them. More likely possibilities include tire pressures were not properly adjusted to compensate for ambient and track temperature conditions, pressures that were off front to rear or rear to front or even side to side. It's impossible to tell without actual data. Other possibilities include suspect suspension geometry or a driving error resulting from being in an unfamiliar vehicle, too much speed, an abrupt turn in or lift throttle oversteer. Or quite possibly some combination of the above and perhaps other unidentified factors as well. Any tire can be over-driven resulting in loss of adhesion and producing a spin.

That said, it's really hard to get a car properly set up for AX. You only get to drive for a minute at a time so your window for getting things sorted out is very small. DE's with 20-30 minute sessions are much easier if you're paying attention. In some smaller AX events you might get to run often enough that your tires actually retain heat and get up to a reasonable operating temperature and stable pressures. At other events you're relegated to chasing cones around a parking lot for an hour in between runs so you have little idea of what is really going on with your rubber. The guys who are consistently fast AX'ers have made a science out of setup and usually have years of experience. One final thing to consider whether it's an AX, DE, NASCAR, Formula 1 or even a bicycle road race for that matter, when conditions are dry what are the fast guys running; slicks or treaded tires? If tread improved dry track performance, they'd be using them. But they don't. Hope this gives you something to think about. Best,

 

Yeah, it surprised me too that there was so little grip coming out of the tires. We did get the pressures as right as we could, given that we had 75 runs over 2 days to adjust them. (probably equivalent to several seasons of autocrossing). We were under no time constraints, and they allowed us to tune as we went. Interestingly, I was able to compare videos of 2010's runs with 3K miles on the PS2s, and they were much more predictable. When I looked at the captured data regarding G forces, they were very similar from year to year. the peaks were all just a hair over 1G. I figure that the biggest "loss" from 3K miles to 14K miles was the predictability of the tire once grip was lost. We also had large variations from run to run. The pressures were relatively stable, but we had no way of taking temp readings of the tires. In 2011 you see lots of sliding and countersteering. In 2010, I had a pro that drives a 911 for SCCA as an instructor, and he found the car very forgiving. I would agree with him on that aspect in 2010 but, in 2011, with only about 10% of tread left on the rears, we would all have described the car as a nightmare. To be fair, Both of the instructors soon adapted to the tires and we set runs roughly equivalent to a few cars running hoosiers. (we were .2 off on a 50 second course). So, the grip was there, but no one felt comfortable with the tires. Next year, i am going back with some RE-11s and get some good runs in!!!!