Why do we care what is happening with some US rules? Because many AARCMCC regulations are derived from ROAR rules, and what happens there tends to have an influence around the world.
Now i never understood the controversy around the bigger 2.4 rims (diameter, not width) were banned last year be ROAR as the rules never allowed them. However the announcement today is an about face from their position in 2014 that is effective immediarely.
Now the height and width of the tyres is not changing, just the size of the rim, and a lower profile tyre will not suit all conditions, just like with 1:1 cars.
If anything i am relieved to see the rule makers moving with the times a little, although i don’t see it changing the nature if how we race much.
ROAR is introducing a rules change with immediate effect that results in 2 different wheel configurations being available as options for manufacturers and competitors: – the existing 2.2″ nominal wheels – the newer 2.4″ or 61mm nominal wheels The new rules do not include dimensions compatible with vintage style wheels as they are generally not used in ROAR sanctioned competition. Dimensions for the traditional 2.2″ wheel will be: – Mounting Bead Diameter – 2.20 inch (55.88mm) +/-.013 inch (.30mm) – Maximum Overall Diameter – 2.42 inch (61.468 mm) – Width – 1.513 inch (38.43mm) maximum Dimensions for the newer wheel style will be: – Mounting Bead Diameter – 2.380 – 2.427 inch (60.45 – 61.65 mm) – Maximum Overall Diameter – 2.571 inch (65.3 mm) – Width – 1.513 inch (38.43mm) maximum