FD: Rule Book change on tire / weight


Cars are limited to the size of the rear tire that can be used, depending on the weight
of the vehicle. There are 7 weight classes, each spanning 200 lbs. A car must be
track-ready, and running when it is weighed and registered to a weight class. A car will
be weighed without the driver, and once the car is registered to a weight class, it will
be recorded, and issued a class-specific sticker that must be displayed prominently on
the windshield. A car’s weight may fluctuate within the limits of it’s weight class, but it
can never weigh less than the minimum weight for its’ registered class. Tire sizes are
AS MEASURED in mm, across the span of the contact patch. Tires will be measured
on the rim, while on the car, while the car is on the ground. Tire size must not exceed
the maximum size dictated by class at any time on track. Tire size will be measured
and verified on track before the start of every tandem round. A Formula D official may
also check tire size at any time during the event.

Weight and Tire Classes-
2000-2199lbs up to 215mm tire width
2200-2399lbs up to 235mm tire width
2400-2599lbs up to 255mm tire width
2600-2799lbs up to 275mm tire width
2800-2999lbs up to 295mm tire width
3000-3199lbs up to 315mm tire width
3200-3399lbs up to 335mm tire width

I’d like to know who runs a 2100lbs car with a 275+ tire and how much they hate this :slight_smile:

The “Dmac” rule. I like it, but then my car already fits those rules. It’s really only going to effect the ridiculously big budget builds where every panel is carbon and half the car is tube chassis. Hell even Matt’s Z is tube in the rear with fiberglass bumpers/hatch and it meets these regs.

I’m sure the big guns like JR, Hubinette, Foust etc will not like this. I’m sure their cars weigh less than 2800lbs and wore larger than 275’s last season.

I also have heard a bunch of guys will be running different engines next year, is there a rule change as far as power plants go as well? ie: JR, Foust, and Dai mentioned it.