Stoptech 127.34029L Disc Brake Rotor - Front Left

StopTech Sport Cross-Drilled & Slotted Disc Brake Rotors Overview

The StopTech Sport Cross-Drilled & Slotted Disc Brake Rotor (Part Number 127.34029L) is engineered for BMW models including the 318i, 318is, 318ti, 320i, 323Ci, 323i, 323is, 325i, 325is, 328i, 328is, Z3, and Z4. Designed to enhance braking performance, this vented rotor features a slotted and drilled surface to improve heat dissipation and maintain consistent stopping power.

• Cross-drilled and slotted surface for improved heat and gas dissipation
• Vented rotor design with straight vane style for enhanced cooling
• Coated hat finish to resist corrosion and extend rotor life
• Floating disc mounting for better thermal expansion management
• Compatible with 5-lug bolt pattern and 286 mm outside diameter

Detailed Product Features and Specifications

This disc brake rotor has a nominal thickness of 21.9 mm (0.862 inches) and a discard thickness of 20.4 mm (0.803 inches), ensuring reliable wear limits for safe operation. The overall height measures 51.7 mm (2.035 inches), and the rotor weighs approximately 6.31 kg (13.88 lbs). The rotor’s center hole diameter is 79 mm (3.11 inches), with a mounting bolt hole circle diameter of 120 mm (4.724 inches) and five stud/lug holes sized at 15 mm (0.591 inches). The rotor surface combines cross-drilled holes and slots to reduce brake fade by allowing gases and debris to escape, while the vented design with straight vanes promotes airflow to keep temperatures down during aggressive driving or track use.

StopTech Sport Cross-Drilled & Slotted Disc Brake Rotors Line

The StopTech Sport Cross-Drilled & Slotted Disc Brake Rotors line focuses on delivering enhanced braking performance through advanced rotor surface technology. This product line is designed to provide improved heat dissipation and consistent brake pad contact, which is critical for BMW vehicles like the 328i and Z4 that demand reliable stopping power under varied driving conditions. The combination of cross-drilled holes and slots in a vented rotor design helps maintain brake efficiency and rotor longevity.

Common Applications and Problem Solving

• Reduces brake fade during high-performance or spirited driving
• Improves heat dissipation to prevent rotor warping
• Helps maintain consistent brake pad bite and stopping power
• Minimizes buildup of brake dust and gases on rotor surface
• Resists corrosion with coated hat finish for longer service life

Installation Notes and Tips

• Ensure rotor thickness is above discard thickness before installation
• Compatible with BMW 318i, 320i, 323i, 325i, 328i, Z3, and Z4 models with 5-lug bolt pattern
• Floating disc mounting requires proper alignment during installation
• Check for ABS tone ring compatibility as this rotor does not include one
• Use recommended torque specifications for mounting bolts

Quality Assurance and Warranty

StopTech disc brake rotors are manufactured to meet or exceed OEM specifications for fit, form, and function. The coated hat finish provides corrosion resistance to extend rotor life. While specific warranty details are not provided here, StopTech products typically come with a limited warranty against defects in materials and workmanship. Always verify warranty terms with the product supplier or manufacturer.