Best Spark Plugs – Reviews & Buying Guide

Spark plugs are small contraptions that deliver the electric current from the ignition system to the spark-ignition engine combustion chamber. All you need to know about them is that you need these little ones for your car or bike.

Top 4 Best Spark Plugs

Spark plugsMain benefits 
NGK TR5IX Iridium IX Spark Plug• Coated with black onyx layer;
• Copper core for optimal insulation;
• Ribbed seal;
ACDelco Professional Spark Plug• Wired Iridium center electrode;
• Heat-active alloy;
• Focused spark plug;
Champion Iridium Spark Plug• Superior quality;
• State-of-the-art components;
• Laser welded Iridium tip;
NGK G-Power Platinum Spark Plugs• OEM specifications standard;
• Trivalent metal shielding;
• Reduced voltage requirements;

How do spark plugs work?

Spark plugs are connected to high voltages that are generated by ignition coils. While the current flows, the voltage develops between sides and center of the electrodes. Without going further into physics, spark plugs simply produce “sparks” that are necessary to run your bike.

When the plug makes “a spark”, it ignites the gas (alongside with the air) in your bike’s engine, setting the energy creation process in motion – at first, a combustion will take place, creating the required energy which will later be transmitted to the corresponding sectors.

Where are the spark plugs located?

Each spark plug has its own place, and that would be the cylinder. Strictly speaking, bikes and cars have various motor cylinders, and each one needs to be filled with a spark plug.

What are the parts of a spark plug?

Spark plugs are very small, but they’re comprised of various smaller parts. They are also differentiated by their function, size, thread, or spark gap. The standard sizes are 100mm, 14mm, 18mm, and sometimes 21mm.


This part is located on the top of a plug and it’s used to connect the spark plug to the system of ignition. Depending on what type the spark plug is, the terminals can be different in shape, design, and size.


Insulator of a spark plug is often constructed of other, smaller parts. The main insulator’s part is often made of sintered alumina (a durable ceramic material that features significant dielectric strength). The brand’s name and the identifying marks are often printed here.


Ribs of a spark plug serve two functions – first of all, they’re used so that you can insert the spark plug into the corresponding place (motor cylinder). Secondly, they greatly improve the insulation of electricity, preventing the energy from overflowing and leaking.

Insulator Tip

Insulator tip (or the top part of the insulator) is often made from the same material as the insulator itself (durable ceramic). The dimensions determine the maximum heat range of your spark plugs. Shorter insulators are often colder spark plugs and vice versa.


Seals allow the final level of sealing the energy from leaking outside. Spark plugs seal the combustion chamber, and the seals help greatly. There are internal and external seals which are both often multi-layered.

Metal case (shell)

Metal case is often called “the jacket”. It is there to endure the pressure of the plug being tightened, it removes the heat that would hinder the insulator, transferring It to your bike’s cylinder head.

NGK TR5IX Iridium IX Spark Plug (4-piece)

Best Spark Plugs - NGK TR5IX Iridium IX Spark PlugNGK’s TR5IX Iridium IX is a set of 4 premium-quality spark plugs. They are designed for superior performance, and each spark plug is comprised of state-of-the-art components. Laser welded Iridium tip makes these plugs durable, and the trivalent metal shielding improves the anti-corrosion properties.

NGK Iridium IX Spark Plugs key specs

  • Superior quality;
  • State-of-the-art components;
  • Laser welded Iridium tip;
  • Trivalent metal shielding;
  • A box of 4 TR5IX 7397 spark plugs;


Buy button


ACDelco Professional Conventional Spark Plug (8-Piece)

Best Spark Plugs - ACDelco Professional Spark PlugACDelco’s CR43%S Professional spark plug set features 8 spark plugs. Each plug is coated with special black onyx layers that prevent corrosion. The core of these plugs is made of copper that allow for optimal insulation and heat transfer. One of the best thing about these plugs is that they feature a nickel-chrome alloy layer on the center electrode. Pretty good for the cash.

ACDelco Conventional Spark Plugs key specs

  • Coated with black onyx layer;
  • Copper core for optimal insulation;
  • Ribbed seal;
  • Nickel-chrome alloy on the center electrode;
  • A pack of 8 spark plugs;


Buy button


Champion REC12WMPB5 Iridium Replacement Spark Plug

Best Spark Plugs - Champion Iridium Spark PlugChampion’s Iridium REC12WMPB5 is a replacement spark plug, but it could also upgrade your older plugs. It features a wired iridium center electrode, the heat-active alloy, and an incredibly fast throttle response. It’s plain and simple, but it’s incredibly good for the price.

Champion Replacement Spark Plug key specs

  • Optimal performance – wired Iridium center electrode;
  • Heat-active alloy;
  • Focused spark plug;
  • Compatible with Chrysler, Hyundai, Jeep, Nissan, Toyota, Ram, Dodge, and Jeep products;
  • A single spark plug;


Buy button


NGK G-Power Platinum Spark Plugs Review

Best Spark Plugs - NGK G-Power Platinum Spark PlugsNGK’s G-Power 4-piece spark plug set was built to the OEM specifications, and each spark plug comes with trivalent metal shielding that provides durability and stability. Using these plugs can reduce the voltage requirements of your bike’s ignition system. Quite affordable, reliable, and very valuable for the cash.

NGK G-Power Platinum Spark Plugs key specs

  • OEM specifications standard;
  • Trivalent metal shielding for optimal durability and anti-corrosion properties;
  • Reduced voltage requirements of your bike’s ignition system;


Buy button

Last words

Aside from replacing your spark plugs, we wrote some more guides on bike and car maintenance. If you’re looking for motorcycle maintenance, it may be worth it to check out our best motorcycle oil guide, as well as our best motorcycle chain guide. If you’re looking more for car maintenance, we got an article on the best brake pads as well as the best HID kits available.

Leave a Comment