(my personal opinion) The suggestion to write gentlemen's agreements on tyres into the rules has been made several times over the years. I strongly oppose it. MSUK provide tyre lists 1A, 1B,1C and we align to them, along with all the other UK speed championships I am aware of. 1. We don't control the spec. of our cars, and have the simplest rules (generaly BHP + tyre list) that we can to keep things as inclusive as possible. Priority is to encourage new entrants. Our championship slowly dies without new people joining. Like many if not most, when I started I took advice that there was a class for my car, don't change anything (other than get an FIA bar, a timing strut and some yellow tape) and just have a go. I figured I would win easily as I am a driving god. If I had been told "your tyres aren't the right ones - they are perhaps too good but we don't really know, we'll tolerate you dabbling, but you won't score points" I wouldn't have bothered. Also, if I'd had to pay for a new set of too sticky or less sticky tyres, I would not have bothered. 3. A new set of ZZS tyres is expensive. Some choose to run on others is List 1B, including 888s, in part to save some money. Lets not tell them they can't score points. 4. ZZS won't be available forever, or might move off list 1B - who knows. There is already a new 1C compound. We don't want to have to study tyres at the end of each season, argue over which is best, change the rules etc. 5. Many spend thousands on optimising their engines for max torque curves and allowed BHP limit, reducing weight, fitting after market dampers etc. Developing your car alongside your driving talent (or in my case to compensate for lack of talent) is part of the sport and part of the club. We have different engines in each class. We don't restrict other modifications. Why restrict tyres beyond the MSUK rules? 6. If someone was rich and daft enough, they'd probably have new tyres for every event, or maybe experiment with shaved new ones for dry and deep tread for wet. Do we try to ban this too? Again, part of the sport. 7. Class 3 seems very healthy as it is. 8. I survived the class 2 tyre wars, Stunners, AD08s, 539s, 15" & 13" wheels. I bought and sold used wheels - it didn't cost much. It made close to zero difference in my times. The best driver won because of their talent, not because of the marginal difference between the best tyres on the MSUK List 1A. I strongly suspect its the same for List 1B. (end of rant )