[glamcem]

Originally Posted by PST

Temperatures were measured across the track surface continually, and averaged across each session. The temperatures matched exactly, to within measurement error. All other environmental conditions were close enough we could not measure a difference.

I understand but still doesn't give us enough information since there are many other factors (engine power, pad/rotor life, etc) that affect the lap times and tires alone cannot be held responsible for the overall lap times, especially when they don't heat cycle out and when the tests haven't been done consecutively

I'm not sure I follow you here... You're saying you think it's more accurate to measure tire temp by going off of pressure readings before and after the session, than to measure tire temps realtime with industrial IR sensors?

yes, take a look at this video, and listen closely after 3:38 mark
[ame="http://youtu.be/YhLzi5f49qE?t=3m38s"]https://youtu.be/YhLzi5f49qE?t=3m38s[/ame]

Keep in mind we're not talking about drifting here. We're talking about a slightly higher amount of slip angle, beyond the peak efficiency of the tire. There's a HUUUUUUUGE difference in drifting around a corner, and a few degrees extra of slip angle. I'm sure you understand the challenges and costs of measuring slip angle realtime, and why that's beyond the scope of this project. We're not testing tires here.

That being said, I'm still researching this behavior I'm seeing. I imagine slip angle vs. temperature is proprietary data that we're not going to find, but I'd like to know if this trend is backed by scientific testing anywhere. I'm not convinced the higher amount of slip is reason enough for the temperature difference. There's no additional energy being turned into noise, or smoke, or anything like that.

Jake I understand your points and agree with most of the things you mentioned here but I have to repeat; that sudden jump on IR temp readings for that specific corner where you see higher corner speed also backs my claim.. it looks like that relationship is pretty obvious, I am not judging the inaccuracy/accuracy of the sensors I am just comparing data horizontally

I appreciate the suggestion, but that would significantly cloud our comparisons. The RE71R is doing fine for our purposes so far, and changing compounds would more or less invalidate any of our previous tests.

it looks like RE71Rs are great tires along with the Direzza ZII and RS3s many people so I agree with you on that

, I was under the impression that you were not satisfied with the results hence the word "degradation" and since you said: " Blue session should have been noticeably faster than the other two sessionsWe simply were not developing the lateral load that we had been in previous sessions. The RE71Rs are still soft, and have about 4/32nds left (rough average). But the grip just isn't there." that is the thing though, we cannot tell the grip wasn't there by looking at the data in hand, especially when almost all the lines are identical..you might as well be reaching the limits of the RE71s since all those lines almost identical except a few places...and average corner speed hike on that 7500-8000 mark seems to be responsible for that (or combination with other factors I mentioned above)

In addition to that, we would expect the tires that don't heat cycle out perform better when tread is less , that's the exact reason why NT01s and many similar tires perform the best right before you see them corded or why people have their Toyo RA1s shaved.. now that totally is a different topic of course

Jake