New Screamin’ Eagle® Tappets (P/N 18572-13, $249.95) from Harley-Davidson® Genuine Motor Accessories® are designed to deliver superior tappet life in high-performance Harley-Davidson Twin Cam and Sportster engine applications. Large, high-capacity needles in the roller bearing assembly improve reliability when operating with high-lift cams, high-pressure valve springs, and in high-RPM applications.
The needle bearings are 25 percent larger to increase the dynamic load rating by approximately 20 percent when compared to the Original Equipment Twin Cam tappets. Sold in a set of four, these Screamin’ Eagle tappets may be used in 1999-later Twin Cam engines, and in 2000-later Sportster Evolution engines. Harley-Davidson.
I’m no mechanical engineer, but this smells fishy. Sure, each individual bearing may have a 20% greater load rating, but with fewer rollers, there is more load per roller. Also, just like with a big axle lifter,the larger roller is going to spin faster.
Again, I’m no engineer and I’m hoping somebody can educate me here and convince me that I’m wrong.
In this application the load isn’t on all the the rollers, just the ones in the line of force, so with either one you only have 2-3 rollers taking virtually the entire force applied. This will be a running change because continuous improvement is H-Ds goal, right? 😉
The ones from Bobby Wood are the way to go !
http://www.woodcarbs.com/dirlifters.htm
I’ll stick with S&S or Feuling…………
I see no need to go away from Fueling!!!!!
Overhung bearings = Unequal load on Needle bearings and inner race. Good luck guys.
I use woods directional lifters on ALL my tc builds or repairs along with his valve springs…
“…because continuous improvement is H-Ds goal, right?”
Good one.
@Industry guy– They aren’t overhung bearings, they are just cut away in the pictures so you can see
the needles. I’ll go with Fueling though, until I hear that nobody has any problems with these HC lifters.