Pro-Challenger Wheels are lightweight “Competitively Priced” Spun Shell wheels with the popular “D” window center. This wheel out performs the rolled shell wheel without the premium spun shell price. The .095" thick spun formed shell mates with a center which is draw formed, stamped and has "Coined 'D' vent windows” to create a strong, lightweight and affordable racing wheel ideal for asphalt racing. Dirt racers will want to add the optional safety beads to keep the tire "locked" onto the wheel.