Hi guys,
I wanted to explain a little bit about how the V7 tires are currently working on the oval cars, as there have been questions asked and ideas on how things are working floating around out there. Hopefully, this will give some insight into what's going on and what we're working on.
Firstly, I wanted to touch base on parts of the tire model where there might be questions or concerns.
Tire fall-off
Depending on the specific race track, tires may or may not fall-of as expected, relative to real world performance. Although our tracks have some differences in roughness, that's picked up in the scans, they all have the same surface abrasion. In the real world this isn't at all the case and makes for very clear distinctions between real track and our versions of them. Some tracks could be faster/slower, or wear more/less than others based strictly on the condition of their racing surface, due to age, aggregate content, etc., besides any differences in shape or distance. The way we've handled this difference has been to alter individual track surface grip on previous iterations of the tire. This was a sufficient way to speed up or slow down pace and impact degradation. V7 interacts with the track in a different manner so a new method is required and is a work in progress. So for the time being many tracks may be either somewhat faster or slower with too little fall-off or too much fall-off. There are some outliers, like Atlanta, which have such large differences in relation to our effective grip level that they are way outside the normal variance - with v6 and earlier huge amounts of track grip was removed to get pace and degradation into a reasonable range. Imagine how fast this place is gonna be with new pavement...
Now I want to caution that the amount of wear and fall-off are directly linked to track temperature and rubber state percentage. Low temps and high rubber states may just behave in a way where fall-off and wear are really low at certain tracks. And that's a trade-off that has to be made to deal with what can happen with really high track temps and low rubber states. In many cases we will find it hard lasting an entire fuel runs, running hard by, say, driving through a tight car or hustling a loose one. This may kill a tire quickly. It's a tight tightrope walk that we'll continue to monitor and adjust as we go. This coming patch moves the goal posts a bit. But do not expect Atlanta to be anything but wide open hot lapping in the Cup car, and maybe others, with anything <100 track temp. It just won't happen for reasons mentioned...Again, it's an outlier. We need other bits to make this track better.
Cold tire performance
The reported issues relating to cold tire performance is caused by a thing called conditioning. Basically, this has to do with 'roughing in' of a tire as it hits the race track with initial scrub and loading - essentially its a softening of a tire that occurs rapidly upon first use. Our tires just aren't conditioning fast enough and it's taking too much time before they are ready to go at a more consistent level. We've been working hard to try to improve the early-run feel but we don't have a great solution yet. However, we know dumping some heat into them accelerate the tire's conditioning, so we've added tire warmers to all V7 tires to give them something of a head start. This phenomenon also explains why it takes, perhaps, a few extra laps before you can achieve the best lap out of the tires.
Temperature readings
There's been commentary about how hot the tires are getting. A tire isn't just one temperature throughout all parts of the tire. There are heat flows, or gradients, which get different parts of the tire hotter than others, of which can change at significantly differing rates. What you see in the garage is actually less a probe temp and closer to a core carcass temp, though still not what a temperature would read at the surface of the carcass on the inside of the tire. As it turns out, it's very important to come up with proper temperature gradients through the tire to get the temperatures to flow correctly to the right degree (pun!). Basically, our tires are still likely running too cool, not too hot, as the build up pressures aren't where they really ought to be in some cases. For example a 25 psi pressure buildup on a right side intermediate tire, starting out at 50 psi and 100 F, requires an inner air temperature reaching 380 F! Basically, we're working on improving this modelling to capture better temperature flows throughout the tire, and once we do that what will get reported will mimic more classical probe readings. Yeah, I know, long time no do...
Max camber
High camber settings will heat up and wear the tires more than lower cambers. Grip will go away if they are set too high. The current limits of 6 degrees, however, are totally reasonable for many situations. Those being colder track temps, short run strategies and qualifying setups. I'd imagine you won't want to run that much with 135 track temp, but know you guys will experiment.
What's working well
We can run more temperature through the tires. This has been a concern in the past, where we had to keep temps much lower than they ought to have been in order to not get too much grip loss, and compared to V6 or earlier versions much less knife-edged response. V7 allows the temps to climb with more reasonable changes in grip through a wider band of slip, just like real tires. There is more to feel, with the nuances of the tires because more time is spent in the plateau part of the slip band rather than climbing a sharp initial ramp and trying to control the past peak performance - the knife-edge bit. The slip curves are, in general, much more correct now. And we can make them even better once we have a better control of conditioning because there are trade-offs there.
Aggressive driving has a time history, it remembers what you have been doing to it, and therefore there are consequences. Over driving, or under driving for that matter, can impact tire life and performance. This version of the tire model has shown to be much more dynamic in terms of driving style and how drivers approach running cars. The V6 tire was very static, with really only one path to good pace with very little that could be done from a driver's standpoint to make up time. Testing has shown this is not the case on V7, with drivers able to conserve and attack at varying points in a tire's life with these decisions coming with their own consequences. Drivers have been able to conserve early and be fast later in a run (or conserve mid-run when it is needed), and others have attacked early and seen greater tire degradation later in the run.
It'll start to be quite evident that setting up the cars to keep tires and chassis well balanced is going to be a very important part of racing strategy. Those who end up driving through tight or loose setups, over the long haul, will notice swings in balance and degradation that could make you pay. You'll easily burn through a right front tire if pushing wide open throttle for too long in a Cup car on an intermediate track like Chicagoland or Texas, but you'll pay for lack of rear drive if you burn off the rear tire at Richmond or the Charlotte Roval.
Finally
The great thing is we've made some really good discoveries in this last round of development, and even during this short patch adjustment period. We've been able to pin-point some areas of major improvement regarding how to better model a bunch of really important, yet subtle, aspects of tire performance. We're working on more precise bits that should make it easier to pump out cars that do more good things in the same manner portrayed in real world tires. I'm pretty happy where we are now as it's more than tuneable in this current form. There will be kinks we'll have to deal with as we continue, obviously, and there will be numerous adjustments need along the way. But what we can do with what we have now is so much more than was possible in prior versions of this model.