NGK TR55IX Iridium Spark Plug, Stock Number 7164, 5/8 Inch Hex, 14mm Thread

The NGK TR55IX (NGK stock number 7164) is an iridium-tip spark plug built on NGK's proven standard-plug platform. It pairs a solid copper core, prized for superior heat dissipation, conductivity, and a broad heat range, with an iridium center electrode tip for durable, consistent ignition. The ground electrode uses a standard configuration with a nickel core, and the plug body is treated with corrosion-resistant plating that keeps installation and removal easy over the plug's service life.

The TR55IX carries a 5k ohm resistor to help suppress ignition noise, a 5/8 inch hex size for standard socket fitment, and a 14mm thread. It is built as an OE-cornerstone design, reflecting NGK's decades of manufacturing reliable ignition components. Always check your engine and maintenance manual to confirm this is the correct plug for your application, and only install a spark plug as recommended by your engine's original equipment manufacturer, since using the wrong plug can reduce performance and fuel economy or damage the engine.

Specifications

• Brand: NGK
• Manufacturer Part Number: TR55IX
• NGK Stock Number: 7164
• Center Electrode Tip Material: Iridium
• Center Electrode Core Material: Copper
• Ground Electrode Core Material: Nickel
• Ground Configuration: Standard
• Resistance: 5k ohm
• Hex Size: 5/8 inch
• Thread Size: 14mm
• Weight: 0.15 pounds
• UPC: 087295171646

Replaces (OEM)

• 73918041131

Frequently Asked Questions

What is the NGK TR55IX spark plug (part number 7164) made of? The TR55IX has a solid copper core center electrode with an iridium tip, paired with a nickel-core ground electrode, and the plug body is treated with corrosion-resistant plating.

Is the NGK TR55IX an iridium spark plug? Yes, the center electrode tip on the NGK TR55IX (stock number 7164) is iridium, while the ground electrode core is nickel.

What hex size does the NGK TR55IX (7164) use? The hex size is 5/8 inch, the standard socket size for this NGK spark plug.

What thread size is the NGK 7164 spark plug? It has a 14mm thread size.

What is the electrical resistance rating of this spark plug? The NGK TR55IX carries a 5k ohm resistor to help suppress ignition noise.

How much does the NGK TR55IX (7164) spark plug weigh? This spark plug weighs 0.15 pounds.

What UPC is printed on the NGK TR55IX spark plug packaging? The UPC for NGK part number TR55IX (stock 7164) is 087295171646.

What ground electrode configuration does the TR55IX use? It uses a standard ground electrode configuration with a nickel core.

Does the NGK TR55IX cross-reference to any other part number? Yes, the NGK TR55IX (7164) interchanges with part number 73918041131.

Is the NGK TR55IX a genuine NGK spark plug or an aftermarket copy? It is a genuine NGK product, built on NGK's OE-cornerstone standard plug design with an iridium tip added for durability.

How many spark plugs come in one package of the NGK 7164? The NGK TR55IX ships as a single spark plug, one per package.

What is the difference between the tip material and the ground electrode material on this plug? On the NGK TR55IX, the center electrode tip is iridium for durability and consistent ignitability, while the ground electrode core is nickel.