I'm considering building a mini and I want to get clarification on tires before I buy anything. The intention of the question is to avoid buying something that will be deemed out of spec if/when I race. I'm not trying to push the rules or get and edge, I just don't want to spend the money on something that will be protested and disallowed.

I've seen the spec state 400x8 and 4.00x8. I Fisly site states 400, but I've seen 4.00 on this site. Are these one in the same? From what I understand, 400x8 is more of a lawn and garden type tire measurement, while a 4.00x8 might be more of a scooter tire measurement.

I've read that the intent of the rule is to put a cap on the overall tire size for the mini class. Apparently this is to avoid a tire size escalation (and expense) that happened in a different class. I'm fine with that and again, this question is not to push the rules any.

I want to use a durable tire that is made for the loads and speeds that I'm using it for. I see that wheel barrow tires are used, but it seems to me that a tire made for the higher mileage and higher speed will last longer. I sail at Ivanpah, CA in the US and that place has a reputation for eating tires. I don't want to have multiple sets on hand in case we get a few high wind tire eating racing days. I can see a wheel barrow tire lasting less than a week at Ivanpah. Those conditions steer me towards a tire made for many miles and higher speed. I find some 3.5x8 and some 4.0x8 scooter tires that I think would work.

The question is whether these tires would violate the letter of the rule. I think a 4.0x8 scooter tire conforms to the intent or spirit of the rule, but that might not hold up to a protest if the rule says 400 and my tire says 4.0. Has there been any discussion of the 400 vs 4.0 that I have missed?

2nd question: I see pics of the mini races at the 2013 Euros and there are clearly mini's racing with wheels and tires that are not 400x8. Especially the front tires - some of them looked like 2x10" wheels. These probably also comply with the spirit/intent of the rule, but not the letter of the rule. How is that allowed?

I don't think I'd have any problems with protests at a Nalsa event because we just don't protest. It just doesn't happen. The 2014 Worlds in the US will have racers from clubs where protests are more common. That is where the letter of the rule might be applied and I want to avoid being on the business end of a protest.

To sum up. What's the deal with 400x8? Are 4.0x8 tires allowed? How are the 2x10's allowed to race? Any thoughts?