This is a reminder that the NHRA Technical Department released back on 4/24/2019 a 2019 Rulebook Amendment Update concerning SFI Specification 15.1, 15.3 and 15.4 wheels. This amendment is shown below in blue underlined text and is in the 2019 NHRA Rulebook Amendments and 2020 NHRA Rulebook located under the Rules section of NHRARacer.com
SECTION 21: GENERAL REGULATIONS, TIRES AND WHEELS:5 5:2 WHEELS (Page 21) (4/24/2019)
Hubcaps must be removed for inspectors, who will check for loose lugs, cracked wheels, worn or oversize lug holes, and condition of spindles, axle nuts, cotter pins, etc. Snap-on hubcaps are prohibited on any class car. The use of “spinner” style wheels or any wheel design that incorporates movable pieces while vehicle is in motion or stationary are prohibited.
Each car in competition must be equipped with automotive-type wheels with a minimum 12 inches of diameter unless Class Requirements stipulate otherwise. Motorcycle wheels or lightweight automotive wire wheels must be equipped with .100- inch minimum diameter steel spokes, properly cross-laced to provide maximum strength. All spoke holes in rim and hub must be laced. Omissions to lighten wheels prohibited. The thread engagement on all wheel studs to the lug nut, or lug bolts to wheel hubs, must be equivalent to or greater than the diameter of the stud/bolt. Length of the stud/bolt does not determine permissibility. (Example: A 7/16-inch stud must be thoroughly engaged through the threads in the hex portion of the lug a minimum of 7/16-inch.)
Wheel spacer permitted. Spacer to be either hub-centric or lug-
centric and must fit with minimal clearance to retain concentricity. The wheel spacer must not reduce the minimum permitted thread engagement below the limits established by fastener diameter. (See example as stated above.) No stacking of wheel spacers allowed. Maximum rim width on any car: 16 inches. No rear wheel discs or covers permitted in any category. Top Fuel and Funny Car rear wheels must meet SFI Spec 15.4. Pro Stock, Top Alcohol Dragster, Top Alcohol Funny Car, and Pro Modified (Comp) must meet a minimum of SFI Spec 15.1.
In Pro Modified, Pro Stock, Funny Car and Top Fuel Dragster, effective April 24, 2019:
(a) any rear wheels originally certified as meeting SFI Spec 15.1 must bear a wheel conformance label indicating compliance with SFI Specification 15.1 properly affixed to each wheel per the specification;
(b) any rear wheels originally certified as meeting SFI Spec 15.3 must bear a wheel conformance label indicating compliance with SFI Specification 15.3 properly affixed to each wheel per the specification (including re-certification if applicable); and
(c) any rear wheels originally certified as meeting SFI Spec 15.4 must bear a wheel conformance label indicating compliance with SFI Specification 15.4 properly affixed to each wheel per the specification (including re-certification if applicable).
In all other categories, effective January 1, 2020:
(a) any rear wheels originally certified as meeting SFI Spec 15.1 must bear a wheel conformance label indicating compliance with SFI Specification 15.1 properly affixed to each wheel per the specification;
(b) any rear wheels originally certified as meeting SFI Spec 15.3 must bear a wheel conformance label indicating compliance with SFI Specification 15.3 properly affixed to each wheel per the specification (including re-certification if applicable); and
(c) any rear wheels originally certified as meeting SFI Spec 15.4 must bear a wheel conformance label indicating compliance with SFI Specification 15.4 properly affixed to each wheel per the specification (including re-certification if applicable).
