The first event of this season I started with an old set of Nitto NT-01s at the end of their life and hoped to get through the weekend on them before I swapped them for new rubber. The temps outside were pretty low and the track is pretty short and easy on tires so it was looking good. I went out for the warmup session and remember thinking how slippery it was and how my car was understeering more on turn in. I was only about .7 seconds off my normal time. I checked my hot pressures and they were right where I liked them so I moved on. The rest of the weekend was the same and after pondering, making adjustments, repeatedly checking pressures and seeing exposed cords at the end I chalked it up to old rubber and forgot about it.
Next up was High Plains Raceway, a much longer track, with elevation change, where grip is key for fast laps. I was showing up with fresh tires, fluids, pads and just had a corner balance and alignment done. I was pumped. First session I go out fully expecting to reset my personal best, but to my disappointment the car was not rotating, sliding again and I was 3 seconds off my normal pace. WTF? It was windy out but 3 seconds? I checked my hot pressures and they were a bit high so I dropped them down and got ready for the next session. I go out and now I am 2.5 seconds off my normal pace… Now I was frustrated. I made adjustments, air pressures were good and it was windy, but man I must be off my game. I was bound and determined to go faster, so I spent the remaining sessions driving harder and harder with no decrease in lap times. No one else is slower than normal so it can’t be the track. What the hell is wrong with me?
After fighting the car all weekend I gave up and decided to pull the data from my best lap and overlay it with my best lap from the weekend to see where I lost so much time. Turns out I was 5-9 MPH slower through every corner but slightly faster at the end the straights as result of my overdriving and late-braking! The good news is that I found a little time there, but I was at the same track 3 weeks prior and was 3 seconds a lap faster. I had not realized it yet, but it turns out I had forgot my tire gauge and borrowed a friends that day.
The next event brought us to a newly paved track, my favorite track in Colorado, Pueblo Motorsports Park. I go out for the first session and I am understeering and 2 seconds slower that normal again… Ok, this blows and I was getting steamed at this point. My air pressures were normal, but for some reason I thought to try my friends brand new, fancy, liquid-filled tire gauge. The gauge read 4 psi higher than mine did! Wait, whaaat. I decided to grab three other friends gauges and do a test. Although they all read slightly different, two of them were identical. One being the brand new liquid filled gauge and the other a high-end, well known brand. So I went with that measurement and went out. Wow, the car is turning again, I am back on normal pace and improving! So how long have I been running my pressures too high? Who knows, but what a relief.
So we returned to High Plains this past weekend and I reset my personal best lap time by .5 seconds, which I am sure is a result of the corner balance done by Velocity Motorsports and the time I found under braking, I am now moving forward with finding more time in the car.
I don’t know when my tire gauge decided to crap out, but I know now that maybe I should not have been so cheap on this important tool. I guess my other lesson here is that even though an air pressure gauge is a simple tool, it’s accuracy is paramount for your performance and in my case sanity so I should have put a little more thought into it. In my car a 4psi discrepancy was worth up to 3 seconds a lap by way of grip at the longer tracks.
In case you are wondering, I had a cheap, generic gauge that I bought from a big box store many years ago and am replacing it with a much higher quality gauge from Turner Motorsport.