Just saw this thread. I race a group 3 MGB, and I race on Nitto NT-01 treaded radial tires. Many of these treaded DOT tires, like the Nitto NT-01 have vintage legal tread, but can/could be shaved down to a point where they only a couple of circumference grooves, really making them a DOT slick. Now SVRA saw this as a problem, whether it be the racer shaving these tires for competitive advantage, or either just wearing them to this point. So I heard SVRA was not going to allow folks to race with the NT-01 at any tread depth next year, OK without being too dramatic, this is deal breaker for me, I absolutely refuse to buy tires that cost $300 more, when then tires I currently run show no advantage, or disadvantage to the higher priced option. I have dedicated my car to radials, this was new for me going into vintage, as long time SCCA slick racer. I like many things about the radial, they don't seem to get hard based on heat cycles like a bias ply tire, they seem to be a lot tougher and less likely to flat spot, I also find them very predictable. So I have huge problem when a few bend the rules and a group responds to this with a broad stroke rule change, my management style differs in that way I just deal with offenders, rather than bother the ones not offending. The way I read SVRA rules now is they seem to be ok with tires like the NT-01 as long as they have good tread showing, which is good, because I would never change my tires to race with any group, but rather avoid that group. This is the kinda of deal where vintage group needs to be very careful, and diligent about what they put out there for rules, otherwise you look up, and they are empty spots in the paddock, because with so many vintage groups to race with, no one needs to play rules king, unless they are OK with results that decision could yield. Vintage groups need to remember, your racers are your customers, do what your customer wants, not what you think is correct. It is always about the customer, and never about the power of leadership, leadership is only successful if they do what the people want. I said this when I raced in the SCCA, and it is very much so applies to vintage racing, find ways to include, rather than ways to exclude, this will always be the more successful path.
Now I did reach out to Rick Parent of the SVRA when I first heard there may be ban on some radial treaded race tires, including the NT-01, and as always Rick as always is easy to talk to, and a very reasonable man, as well as racer's racer. Rick invited me to talk to him about this on phone, and the only reason I have not, is because I have raced any this year, and I've never found Tony, or Rick to be unreasonable people, and they always seem to have a open ear to their customers.
I will be curious to hear about your conversation with Rick Parent about the Nitto tires. We (VDCA) follow the SVRA tire rules. Mostly because I have zero time and even less interest for concocting my own set of tire rules.
I hate to have rules that increase the costs for our competitors but I can tell you that I will not be making a list at every event of who is running what tire and then scurrying around measuring tread depths. If there is a another solution, I'm all ears.
Doug well hopefully it is not a issue, with groups like the VDCA, VRG, VDCA, because half or better already run these tires on their MGBs, in the VDCA, I would say over half run these tires. There tons of results out there showing there is no pattern of Nitto, vs Hoosier and neither one being more dominant. At the MGVR focus event we see about 50-50 split on the MGBs, and last MGVR at Waterford, the winner was on Nittos, 2nd place on his tail at the finish, had fastest race lap, and he was on Hooisers, there is tons of data out there with this sort of info. The Nitto last longer, cost $300 less, and hard to flat spot, or damage, just a more rugged tire in general. I'd say on decent MGB vintage race one can get 8-10 weekends out of set of Nittos.