If you remember about 12 months ago I posted a problem with my Astra Coupe trying to pull to the left. The behavior was if you took your hands off wheel, the steering wheel would instantly move left by about an inch, I also had to steer slightly right to keep the car straight. The problem was there for about 18 months, and in that time had the car tracked twice but both times they said the tracking was perfect. I checked tyre pressures regularly, I had no idea what it was, and could not point exactly when it started. The only thing sure was it was worse with someone in the passenger seat. To be honest I thought the geometry must be out. The car had 4 x new F1 tyres fitted.
Anyway, this weekend I replaced both my front F1 tyres for some brand new F1 tyres, keeping the exact same pressure. The tracking problem has totally gone, and if anything it’s now pulling very marginally to the right (not left). I would not have believed tyres could have made that much difference, I can only conclude one of the F1's had a slight defect. Either way the cars driving much nicer, never driven this good before.
On Monday I will phone my tyre fitter and ask if he noticed anything strange when he took the old tyres off.