DigitalRelay
Premium
- 194
- Phoenix, AZ
- DigitalRelay
I was practicing for a league race recently, Gr3 911 at Willow Springs BOP with tire wear at 4x, and I noticed my tires were wearing out far more quickly compared to other drivers. I have a dedicated display unit on my sim rig which shows tire temperatures and after more practice, it seemed like if I kept the tire temps under 195°F or so, the tires lasted longer. It made me wonder if there was a threshold limit or exponential slope and if I could find what those thresholds were. After searching for the information and finding a few clues - a Kierth video showing increased wear at higher temps, a Tidgney video that referred to "around 90°C" being the limit, and a Wombleleader video that narrowed it closer to 88°C on racing softs - so I decided to do my own testing.
I setup a custom race in GT7 update 1.55 at Northern Isle Raceway for 10 laps in the same car with tire wear at 4x and capture the in game footage, while separately capturing the tire temp overlay on my laptop and syncing the footage after the fact. I ran five full races on racing soft tires. While monitoring temps on my DDU, I tried to keep temps at 180°F the first race, 185°F the second, 190°F the third, 195° the fourth, and 200° the fifth. I then repeated this test on racing medium tires, but I added a sixth race where I pushed as hard as a I could ignoring temps, which went over 220°F. I did one more test on racing hards, but cut it to three races - 185°F, 195°F and pushing hard with temps over 220°F again. I went back to the footage and paused crossing the line on the last lap and took a screenshot of tire wear, then overlaid the tire temp aim from that session. After compositing the screenshots for easier comparison, here are the results.
It appears to me that each compound has a different threshold. It also appears the relationship of heat to tire wear is sloped or curved, and that each compound has a threshold where the curve gets exponentially worse. For racing soft tires, I think it's around 190°F/88°C. For racing medium 194°F/90°C. For racing hard 199°F/93°C.
A couple other notes...
I was surprised just how hard it was to maintain tire temps like this. I had many restarts if I either slide and the temps spiked, or if I went over the target temp by a few degrees because it would take several laps of slowing down to try to get them to come back down. It seemed like once that heat is in the tire, it takes time for them to come back down. I found pushing a little hard the first 3 laps brought the temps up, then I'd adjust my driving to lift going into the turns, coast and then slowly apply throttle as the turn straightened up. This was pretty much the approach Tidgney mentioned in his video as a tip to avoid overheating tires.
Going into this, I knew tire temps were a thing, and that sliding and spiking temps made grip worse, but I now have a much better understanding that the relationship of tire temps to wear is more complicated than that.
One last thing, if you're racing in races where tire wear is a factor, I think you'd want to consider having a way to monitor tire temps in real time. That could be an app on your phone or tablet, a laptop, or a dedicated display unit. I have used Eziodash on my iPhone and it looks and works great, but trying to go back and forth using it as my phone and a dash was a total pain. A spare smartphone or tablet would be better. Since I'm already running Simhub for bass shakers, wind simulation, and rumble pedals, it was very easy to add a $44 Vocore screen, 3D print a housing and mount it on my rig permanently.
I posted a video on my YT channel going into more detail on testing and what I learned.
If you have insight that I might have missed, I'd love to hear it.
I setup a custom race in GT7 update 1.55 at Northern Isle Raceway for 10 laps in the same car with tire wear at 4x and capture the in game footage, while separately capturing the tire temp overlay on my laptop and syncing the footage after the fact. I ran five full races on racing soft tires. While monitoring temps on my DDU, I tried to keep temps at 180°F the first race, 185°F the second, 190°F the third, 195° the fourth, and 200° the fifth. I then repeated this test on racing medium tires, but I added a sixth race where I pushed as hard as a I could ignoring temps, which went over 220°F. I did one more test on racing hards, but cut it to three races - 185°F, 195°F and pushing hard with temps over 220°F again. I went back to the footage and paused crossing the line on the last lap and took a screenshot of tire wear, then overlaid the tire temp aim from that session. After compositing the screenshots for easier comparison, here are the results.
It appears to me that each compound has a different threshold. It also appears the relationship of heat to tire wear is sloped or curved, and that each compound has a threshold where the curve gets exponentially worse. For racing soft tires, I think it's around 190°F/88°C. For racing medium 194°F/90°C. For racing hard 199°F/93°C.
A couple other notes...
I was surprised just how hard it was to maintain tire temps like this. I had many restarts if I either slide and the temps spiked, or if I went over the target temp by a few degrees because it would take several laps of slowing down to try to get them to come back down. It seemed like once that heat is in the tire, it takes time for them to come back down. I found pushing a little hard the first 3 laps brought the temps up, then I'd adjust my driving to lift going into the turns, coast and then slowly apply throttle as the turn straightened up. This was pretty much the approach Tidgney mentioned in his video as a tip to avoid overheating tires.
Going into this, I knew tire temps were a thing, and that sliding and spiking temps made grip worse, but I now have a much better understanding that the relationship of tire temps to wear is more complicated than that.
One last thing, if you're racing in races where tire wear is a factor, I think you'd want to consider having a way to monitor tire temps in real time. That could be an app on your phone or tablet, a laptop, or a dedicated display unit. I have used Eziodash on my iPhone and it looks and works great, but trying to go back and forth using it as my phone and a dash was a total pain. A spare smartphone or tablet would be better. Since I'm already running Simhub for bass shakers, wind simulation, and rumble pedals, it was very easy to add a $44 Vocore screen, 3D print a housing and mount it on my rig permanently.
I posted a video on my YT channel going into more detail on testing and what I learned.
If you have insight that I might have missed, I'd love to hear it.
since im driving in vr I cannot use a temperature display, but it still helps to estimate how to drive careful enough if one sees that the degradation grows exponentially.
