Tire pressure guide to farpection


Back in my HPDE days I would never bother with tire pressures. Racing in Iracing taught me that there are seconds to be won and lost just with tire pressures. I am not a perfectionist, but I love having rules that gives me the 95th percentile of the result.

3 rules you need to know.

  • 1 tire pressure is linear with sidewall temperature. 10F= 1psi change. A 70F tire will have 3 psi less then a 100F tire. So measure the sidewall prior to deflating a “cold” tire if was sitting in the sun.

  • Get a Set your tires cold and adjust the difference when hot after a session. A cold tire is much more stable to measure, after knowing how they feel, you can measure it cold again then use it as a baseline.

  • Use the same tire pressure gauge & temp sensor for all measurements. Gauge are precise tools, but can become offset with time. What is interesting is once verified “wrong” you just need to remember the offset. Mine is off by 4psi, but 1psi still =1 psi difference.

For example. I set my tires at 26psi cold @ 60F per gauge 1. New gauge reads 30psi at 60F. At the track, I had a flat because of a valve stem issue. 12psi @ 110F with gauge 2. Bumped the air up to 35psi. Make sure the tire temp doesn’t drop during that period.

Conclusion, next time you have a great weekend, measure the tire pressure and side wall temp when home. That way you can use it as a baseline for the next track day.


You’re my new tech hero. I usually set them in the morning and then again in the afternoon after lunch. I don’t use math.