Pencil gauges aren’t accurate. I worked at a tire shop for years and used tons of them. Maybe 2 out of 5 would be off by 2psi when new. They start off reasonably consistent. But then they get dirty, get dropped, and wear so they lose that too. They are fine for street car tires but I’d never use one at the track on any vehicle. It’s funny, the shop had a “master” pencil gauge stored in a case that was almost never used. Even that one didn’t match my verified Longacre digital.
