I don't know, I look at the Drag Week classes, and I do not have a car that really fits any of them. All my stuff is big tire, even my AFX car....So that leaves me looking to see what I can change if I want to join the event some year. What I find surprising is the Gasser class is limited to 11.5" max...Can't say I ever remember tire limits on Gassers.
My best guess (with a modicum of background) is that the tire size rule is based on tire sizes available during the gasser era (pre 72 - pure gas class era). There were no limits then because a giant tire back then was a fueler tire and by todays standards not big (32"-13 ish)
