**Spec Stud Rules**

**Updated 11/2/2023

• Maximum stud quantity per tire is limited.  See the charts available here: Spec Stud Qty Charts

  • • Tire size/stud quantity may be different on front and rear tires, but no more than the maximum allowed quantity per that specific tire size.  For example, you may run staggered set up of 225/40R18 front tires and 255/40R18 rear tires. 168 front tire studs are allowed and 197 rear tire studs.  You may NOT run 197 studs in the 225/40R18 front tires because you are using 255/40R18 rear tires.

• Construction is limited to:

  •  Maximum 5/16” diameter (M8 metric bolt) by 1-1/4” (32mm) length steel hex or flange head bolts for tires with 7/32" or greater of measured tread depth, or 5/16” diameter (M8 metric bolt) by 1” (26mm) length steel hex or flange head bolts for tires with 6/32" or less of measured tread depth .  The maximum length of the bolt is to be measured from the mating surface of the hex head, or the mating flange of the flange bolt (L dimension in figures shown) to the end of the bolt (sharpened or unsharpened).

  • Minimum included angle of the sharpened bolt to be 45º. (For example; Studs sharpened at 30º are not allowed)

    • Bolts sharpened to included angles greater than 45º are NOT allowed.

    • The use of smaller diameter, or shorter length bolts than maximum for your tire are allowed.

    • There is no minimum or maximum measurement for stud protrusion outside the tire tread.  Stud protrusion will be determined by your style washer/nut used and amount of tread on the tire they are built on.

    • The use of specialty bolts such as snowmobile style studs, or anything other than a generic sharpened Hex/Flange head bolt is not allowed.

• Tires must be DOT approved passenger car tires.  No specialized race tires such as rally race tires allowed. 

• Stud pattern of the tires is not limited in design but should be symmetrical/repeating about the tire.  E.g. placing more studs more densely on the outer or inner shoulder of the tire is NOT allowed.  Pattern should be symmetrical both in the width across the tire and the circumference.  

**As always, the club board members reserve the right to make final decisions on what is and what is not allowed.  If you have questions about whether what you are making is going to be allowed, please contact us BEFORE making the tires