MAHLE 3021275B Performance Steel Napier Piston Ring Set Bore - THM-13 4.185 1.5mm

The MAHLE 3021275B is a high-performance steel Napier THM-13 piston ring designed for precision engine builds requiring a 4.185-inch bore diameter. This professional-grade ring features a 1.5mm ring thickness with a 0.150-inch radial wall dimension, engineered to deliver superior sealing and durability in demanding performance applications.

Key Features:

• Steel construction provides exceptional tensile strength, hardness, and fatigue resistance for high-performance engines
• Napier THM-13 hook groove design offers superior oil control by scraping cylinder walls and creating an oil reservoir on each down stroke
• 1.5mm thickness allows for reduced friction while maintaining excellent ring seal and compression
• 0.150-inch radial wall dimension ensures optimal cylinder wall contact and sealing
• Bulk plain ring set configuration for professional engine builders and shops
• Pre-lapped design for immediate seating and virtually eliminates break-in time

MAHLE performance piston rings are developed using advanced piston ring simulation and computer development tools to minimize friction and maximize horsepower. The steel alloy construction resists ring breakage, reduces side wear, and minimizes ring groove pound-out problems common in high-stress applications. Suitable for racing engines, high-performance street builds, and engine rebuilds where premium components are required.