Spec tires for 12th has got to be the most ridiculous thought. While I understand why people think it may be a good idea, the truth is, no, it really is not.
First, 12th scale, no matter what kind of spec'ing is not really a beginners class, so why try to make it way. Most new racers do not see the minute changes and tweaks to 12th scale cars, and trying to " work around " a spec set of tires would be infuriating, and they would go buy a slash or a taxicab as I have heard Ian call them...
Second, we have a few combinations that work, and they work pretty much everywhere, so pick a combo and make it work. ( kind of personal spec'ing ). The only place a spec tire would make any kind of sense is at the club level, and they are pretty much spec's anyhow, kind of Darwinesque... So what is the point.
In EVERY type of racing. People look for an advantage, and they try different things, a 10 dollar set of tires is not make or break. In a class like 12th scale, you NEED to keep the experienced racers in it, it will wither away without that experience. They have raced it for 20+ years, and have seen all the changes, if they feel a spec tire is bad idea.... well it probably is.
another thing while on my soap box ...
Club or newer racers want to get the most out of their tires anyhow, and will not cut them down to the size that is needed to win at any competitive track. The point here... is does not matter the tire, to be competitive you have to whack it down pretty low... so your buying tires , no matter what they are.. pretty frequently. Whats the the big deal buying a different set here and there to "try" and find a better combination for the individual... and on that point... I am sure spec tires will have a "sweet spot" in diameter, and that will be track to track, car to car.. blah blah.... not really spec anyhow... Tires are tires.. and 12th scale tires are cheap.... You want to bitch about tires.. go run offroad... what a joke.
who knows, I am pretty much full of sh^& anyhow