Iridium Plugs
Stellar HDF Member
Joined: Mar 2011
Posts: 3,482
Likes: 631
From: NorCal Rocklin
This guy does a great job of laying out the differences of fake vs legit. His part number is different than mine, so his readings were different, but mine were all 6.0xx K.
https://www.youtube.com/watch?v=vpH4...nnel=dial2fast
https://www.youtube.com/watch?v=vpH4...nnel=dial2fast
Seasoned HDF Member
Joined: Sep 2009
Posts: 17,148
Likes: 6,170
From: SE Michigan
Or just buy Harley plugs and live your life, experiencing the wonderfulness of not paying more for nothing.
Road Warrior
Joined: Nov 2022
Posts: 1,541
Likes: 543
From: MN
First there was platinum, then iridium, now rhodium.
The purpose of rare earth metal coatings is to extend electrode life by not transferring as much metal ions as original nickel coated electrodes. Some of us remember changing plugs every 12,000 miles in any vehicle engine. Those were the nickel coated original plugs.
Generally (look it up), platinum goes 50,000 miles without degradation, iridium 100,000, rhodium 150,000.
You need higher voltage to jump the spark gap the more resistive the coating. Supposedly (according to NGK website), rhodium provides higher resistivity but more dense spark than iridium or platinum.
A guy would need to know if the ignition system on any particular motor was set up to run with higher resistivity plugs. I stick with OEM recommendation for this reason - I don't know what their system can handle or what it runs best on.
The purpose of rare earth metal coatings is to extend electrode life by not transferring as much metal ions as original nickel coated electrodes. Some of us remember changing plugs every 12,000 miles in any vehicle engine. Those were the nickel coated original plugs.
Generally (look it up), platinum goes 50,000 miles without degradation, iridium 100,000, rhodium 150,000.
You need higher voltage to jump the spark gap the more resistive the coating. Supposedly (according to NGK website), rhodium provides higher resistivity but more dense spark than iridium or platinum.
A guy would need to know if the ignition system on any particular motor was set up to run with higher resistivity plugs. I stick with OEM recommendation for this reason - I don't know what their system can handle or what it runs best on.
Seasoned HDF Member
Joined: Jan 2006
Posts: 11,475
Likes: 3,001
From: Charleston, SC
The NGK plug is cheaper than the HD equivalent. I'd rather experience the wonderfulness of not continuing to give HD extra money for nothing. Literally just a spark plug. Not expecting anything but for it to work and for my life to continue on.
Last edited by lp; Sep 27, 2023 at 06:32 PM.
Thread Starter
|
Seasoned HDF Member
Joined: May 2018
Posts: 5,814
Likes: 7,147
From: Las Vegas
Does HD have an iridium plug? I thought the Screaming Eagle was double platinum?
Seasoned HDF Member
Joined: Jan 2006
Posts: 11,475
Likes: 3,001
From: Charleston, SC
Just the Platinum. 30 bucks for two. Been running those for the last 30K miles, so time to change them out probably.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Seasoned HDF Member
Joined: Aug 2006
Posts: 24,528
Likes: 30,845
From: Pennsylvania
Had a set of iridium plugs in our 2002 Toyota Avalon, they lasted 280,000 some odd miles with no change to gas mileage etc. I did not change them out as the rear 3 on the transverse engine required pulling the intake manifold. When I had my garage change the timing belt, water pump, valve cover gasket (was leaking a tiny bit) I told them to pull the manifold and replace the plugs at the same time. Son drove that car through High School & College, he traded it in with 358,000 miles on a 2020 Genesis G70.
I expect our 2013 Lexus E350 has iridium plugs also, it currently has 180,000 miles on it, maybe I"ll pull one of the front plugs and see what it looks like.
I am of the mind if it is running okay and the gas mileage has not changed to not change the plugs out. To each his own, I'm not cheap I'm thrifty.
I expect our 2013 Lexus E350 has iridium plugs also, it currently has 180,000 miles on it, maybe I"ll pull one of the front plugs and see what it looks like.
I am of the mind if it is running okay and the gas mileage has not changed to not change the plugs out. To each his own, I'm not cheap I'm thrifty.
