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Ruthenium vs Iridium Spark Plugs

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Spark plugs play a critical role in powering your vehicle. They provide the spark that ignites your engine’s fuel, generating power to move your vehicle forward.

You can get plugs made out of different materials, each with its advantages and disadvantages. Some provide more power. Some last longer. Some offer great value. It’s important to know which is which so you can choose the right ones.

Two rarer options are ruthenium and iridium, which may sound more like parts of a spacecraft than actual metals. We’ll cover the advantages and disadvantages of buying spark plugs made out of each.

Pros and Cons of Ruthenium Spark Plugs

Ruthenium Spark Plug

Ruthenium spark plugs are new. They have central electrodes coated with ruthenium, a hard, silvery metal. They also incorporate the latest in spark plug technology.

Here’s a quick list of pros and cons:


  • Fuel Efficient: Ruthenium spark plugs ignite the best, making the most of your fuel.
  • Low Waste: Ruthenium spark plugs create little waste, so they cut exhaust and boost efficiency.
  • Faster Acceleration: Burning the fuel-air mixture completely provides more power to your engine. Cars with ruthenium spark plugs can accelerate faster.
  • Value for Money: They are cost-effective spark plugs.


  • Rarer: Ruthenium spark plugs are new technology, so can be difficult to find.
  • Vulnerable to Weather: Extreme weather conditions will cause durability issues.
  • Wear and Tear: Faster revving engines can cause wear-and-tear to speed up.

Pros and Cons of Iridium Spark Plugs

Iridium Spark Plug

Iridium is a hard, silvery metal used to coat the central electrode of spark plugs. It has a solid reputation as an improvement over older spark plug makes.

Here’s a list of Pros and Cons.


  • Durability: They’re highly durable and las a long time. They’re also resistant to corrosion.
  • Advanced Tech: Their design will improve performance, especially over older spark plug designs.
  • Superior performance: Especially in extreme conditions like temperature or traveling on steep grades, these plugs outperform their competitors.
  • Fuel efficiency: These plugs are more efficient than older alternatives.


  • Expensive: You’ll pay through the nose for iridium spark plugs. If you want performance, this could be worth the cost.
  • Less Efficient than Ruthenium: Before ruthenium spark plugs, they provided the best ignition of your fuel-air mixture. Now, they are the less effective option.
  • Brittle Metal: Iridium itself is a brittle metal, so take care in installing them. The slightest bump could damage them and degrade performance.

Is Ruthenium Better Than Iridium?

Ruthenium spark plugs are newer than iridium. That doesn’t mean they are better, just that they are more advanced in some respects. There’s a trade-off in performance that you’ll want to know about.

Ruthenium offers a more complete combustion. That means burning all of the fuel-air mixture provided to your engine. This will give you extra power and faster acceleration. It will also mean better fuel efficiency. They can also last as long as 120,000 miles.

Iridium is a harder metal than ruthenium, so spark plugs with it coating the central electrode have better durability. Under extreme conditions, they will stand up better. It’s also brittle, so it might chip if you are careless during installation. They also last approximately 60,000 miles.

Iridium is also expensive. Before ruthenium spark plugs, you could have argued that the performance was worth the price. Ruthenium’s better ignition means you need to weigh carefully whether you’ll get value from buying them.

Differences Between Ruthenium and Iridium Spark Plugs

Spark Plugs

From a performance standpoint, ruthenium spark plugs ignite more of your vehicle’s fuel-air mixture. They are also affordable and last a long time. Ruthenium spark plugs might last as long as 120,000 miles depending on the make and model of your vehicle.

Iridium spark plugs can withstand extreme conditions – weather and tackling steep grades – better. Iridium can be brittle, so they require care while installing them. If you get them in right, however, they’ll last for approximately 60,000 miles.

Ruthenium spark plugs have two configurations. Double-find electrode plugs are best used in regular vehicles.  Projected square platinum electrode plugs are best used in supercharged vehicles.

From a performance standoff, you might find ruthenium a better value. Iridium might be better if you often drive in extreme conditions.

The reason for these differences comes from the two different metals used in the plugs.

Ruthenium comes from the iron family of metals. These metals are dense and have high melting points. Ruthenium’s melting point is approximately 2,333 degrees Celsius.

Iridium comes from the cobalt family of metals. These metals are brittle, are known to be toxic, and are also highly dense. Iridium’s melting point is approximately 2,000 degrees Celsius.

Is Ruthenium Harder Than Iridium?

Ruthenium and iridium are known as transition metals. Transition metals are easily shaped and are good conductors of heat and electricity. Both are also considered hard metals.

While both are hard, ruthenium is a little more robust than iridium. Spark plugs made with ruthenium are expected to last a little longer than spark plugs made from iridium.

Iridium is more brittle than ruthenium. While better than traditional spark plugs, they are easy to chip during installation. That will degrade performance.


Compared to older makes of spark plugs, ruthenium and iridium provide superior performance. Both provide a better spark to burn your fuel-air mixture more completely. That means more power and better efficiency.

Of the two, ruthenium plugs offer better power at a lower cost. Iridium plugs last longer and provide much better performance in extreme conditions.

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