Park Tool CC-4.2 Chain Checker

Preserve your bicycle's shifting performance and protect expensive drivetrain components with the Park Tool CC-4.2 Chain Checker, the industry-standard tool for measuring chain elongation. A stretched chain creates poor shifting quality and accelerates wear on cassettes, chainrings, and derailleurs, leading to costly replacements that could be easily prevented.

This precision-engineered drop-in gauge eliminates uncertainty when determining chain replacement intervals. The laser-cut CC-4.2 evaluates chain stretch across an extended chain segment, making contact at three strategic points to deliver reliable measurements every time. This go/no-go design provides instant feedback, removing the complexity from chain maintenance decisions.

Engineered for versatility, this chain wear tool accommodates any 5 to 13-speed chain, including modern high-performance chains like SRAM® T-Type, SRAM® Flattop™, Shimano® 12-speed, and Campagnolo® Ekar™ 13-speed variants. Single-speed applications are equally supported. The gauge precisely identifies 0.5%, 0.75%, and 1.0% elongation thresholds – the critical replacement points recommended by leading chain manufacturers.

Regular chain monitoring with this professional-grade tool maximizes component lifespan while maintaining optimal shifting performance. Remember that different drivetrain manufacturers may have specific replacement guidelines, so always verify recommendations for your particular setup.

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Features:

• Drop-in gauge design for effortless operation
• Precision laser-cut construction ensures measurement accuracy
• Extended chain section evaluation with three-point contact system
• Simple go/no-go gauge eliminates measurement interpretation
• Universal compatibility with 5 to 13-speed chains
• Single-speed chain compatibility included
• Supports SRAM® T-Type chain technology
• Compatible with SRAM® Flattop™ chain designs
• Works with Shimano® 12-speed chains
• Supports Campagnolo® Ekar™ 13-speed systems
• Clearly indicates 0.5%, 0.75%, and 1.0% wear thresholds
• Eliminates guesswork from chain replacement decisions

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Specifications:

• Chain Compatibility: 5 to 13-speed derailleur and single-speed chains
• Wear Measurement Points: 0.5%, 0.75%, and 1.0% elongation
• Construction Method: Precision laser-cut manufacturing
• Gauge Type: Drop-in style measurement tool
• Measurement System: Go/no-go gauge design
• MADE IN USA